Sefer Haminhagim - Chabad Lubavitch Customs
On the seventh of Adar (the anniversary both of the birth and of the passing of Moshe Rabbeinu) and at the preceding Minchah, the Rebbeim of Chabad never said Tachanun. This was the case after they had assumed the leadership, never beforehand. 
Purim Laws and Customs of General Application 
"When Parshas Zachor is read on the Shabbos before Purim, (and likewise when it is read on the Shabbos of Parshas Ki Seitzei [from which it is drawn]), there are varying traditions as to how to pronounce the word zecher, whose first syllable can be vocalized either with a tzeirei or with a segol.
The same doubt exists when this word appears in the Torah reading of Purim, (and likewise on the Shabbos of Parshas Beshalach [from which it is drawn]).
Here, too, I have not received a specific directive.
"It would appear that in each case the word Zecher should be read twice.
On Shabbos Zachor (and in Parshas Ki Seitzei) it should first be read "zaicher" vocalized with a tzeirei and then vocalized with a segol as "zecher".
In the Torah reading of Purim (and in Parshas Beshalach) it should also be read twice, but with the vocalization in reverse order." 
At Shacharis on the Fast of Esther we say Selichos (Siddur, p. 359ff.) and Avinu Malkeinu (p. 277ff.).
The [three] coins of half a shekel (machatzis hashekel) are given [to charity] on the fast day, even when Purim falls on Sunday, [in which case the fast is observed on the preceding Thursday].
In the Megillah written by the Rebbe Maharash,
- not all the columns begin with the word HaMelech
- nor do the names of the ten sons of Haman (Esther 9:7-9) occupy a separate column. 
Those listening  to the reading of the Megillah fold their scroll [just as the reader does] like a letter,  into three parts.
It is customary to "strike Haman" [by means of noise-makers and the like] at the mention of his name, at various stages in the reading (i.e., when he is described by an epithet, such as Agagi "the descendant of Agag," or HaRasha "the wicked"). 
In the Megillah (8:11) we read le'harog v'la-abaid and then v'laharg u'labaid, and (in 9:2) we read v'ish lo amad bifneihem and v'ish lo amad lifneihem. 
The Megillah is rustled at the mention of the words ho-igeres hazos "this letter"; (9:26) and again at igeres haPurim hazos hasheinis "this second letter of Purim"; (9:29).
We recite the blessing of Shehecheyanu (Siddur, p. 339-340) by day as well [as at night]. 
On Purim day the tefillin of Rashi are worn when the Megillah is heard and read. 
The wording in Shoshanas Yaakov (Siddur, p. 340) is: Arurim kol ho- reshaim bruchim kol hatzadikim "Accursed be all the wicked, blessed be all the righteous." 
Minchah is held earlier that usual and is followed by the seudah, the festive meal of Purim.
The rejoicing of Purim far surpasses that of Yom-Tov. 
The days of Purim  are days of feasting and joy. 
Customs of the Rebbeim 
A silk coat is worn, as on Shabbos or Yom-Tov.
Half-shekel coins are given on behalf of the Rebbitzin and for young sons and daughters.
Even in private (i.e., even without a minyan) the blessings before and after the Megillah are recited, both by night and by day.
Mishloach Manos (gifts of food; Esther 9:19), comprising food and drink, are sent to three people.
A sable hat and a gartel are worn for netilas yadayim, the blessing of HaMotzi and the Grace after Meals, and for the maamar.
A maamar is delivered at the festive meal.
It is the custom of the Rebbe Shlita to make an appeal during the farbrengen on Purim. 
- (Back to text) From the Notes of the Rebbe Shlita.
- (Back to text) [For an understanding of Purim as explained in the teachings of Chassidus, see the English translation of the maamar of the Rebbe Rayatz, entitled Vekibeil HaYehudim 5787 (Sichos In English, N.Y., 1991).]
- (Back to text) In Parshas Beshalach, the Masorah on the Chumash records that zaicher is vocalized with a tzeirei; in Parshas Ki Seitzei, it cites both views. This is evidently what the author of Mishnah Berurah had in mind when he ruled (in sec. 685:18) that the word should be pronounced both ways in order to satisfy both requirements. (Conflicting oral traditions are noted in Maaseh Rav and in the Glosses appended to it; see also Haggahos Poras Yosef on Bava Basra 21b.)
Accordingly, the doubt should involve only Parshas Ki Seitzei (and Parshas Zachor). However, the Notes at the end of Vol. IV of Ketzos HaShulchan cite varying customs for the reading of Parshas Beshalach as well; grounds for them may be found in the light of the explanations given in Boneh Yerushalayim, sec. 44, though the latter appear to disclose a certain degree of inaccuracy.
In view of the explanation there that the segol is more relevant to Parshas Beshalach and the tzeirei more relevant to Parshas Ki Seitzei, it seems to me, as recorded in the text above, that in Parshas Beshalach (and on Purim) the word should first be pronounced with a segol, as the reading proper; then, in order to also satisfy the alternative view, it should be repeated with a tzeirei. In Parshas Ki Seitzei (and for Parshas Zachor) the order should be reversed.
Moreover, since the reading for Maftir is supplementary to the reading proper (for which the preceding seven congregants are called to the Torah), the above-described arrangement should apply both when the final passage is read for the seventh congregant and when it is repeated for the Maftir.
As to what, in the final analysis, really matters, the author of Toras Chessed, quoted in the above-mentioned Ketzos HaShulchan, had this to say: "Let it be zecher, let it be zeicher - so long as [the kelipah of one's personal Amalek] is erased once and for all!"
- (Back to text) A facsimile of this column is to be found in Sefer HaToldos of the Rebbe Maharash, p. 21. See also Shulchan Aruch, Orach Chayim 691:4, with Ba'er Heitev and Shaarei Teshuvah, and the sources indicated there; and Sdei Chemed, Aseifas Dinim, end of the section on Purim.
- (Back to text) "There are no grounds to support the suggestion that one can fulfill the obligation of hearing the reading of the Megillah and so forth by means of a telephone, radio, or the like. For what is heard is not a man's voice at all (and does not even resemble the case of `one who sounds a Shofar in a pit'). It is obviously most novel, even strange, to suggest that an indirect effect (Koach Kocho) and a basic transformation of the very nature of speech, should serve as a substitute for speech.
"Even though the recent scholars who have ruled otherwise include reputed poskim, it is evident from their very Responsa that those who explained them the nature and workings of the telephone made a basic mistake.
"At any rate, this is not the forum for a more extensive discussion of the subject." (From a letter of the Rebbe Shlita [reprinted in Teshuvos U'Biurim, p. 242].)
- (Back to text) See the commentaries on the Shulchan Aruch 690:17. The reason derives perhaps from the statement in Pri Megadim (Eshel Avraham, end of sec. 689), cited in Derech HaChayim, that it is proper that every individual have a valid Megillah, which thus needs to be unrolled and folded.
- (Back to text) Shulchan Aruch, loc. cit., and its commentaries. The compiler of the Siddur Yaavetz (R. Yaakov Emden) records that his father (the Chacham Zvi) used to stamp with his feet and clap with his shoes when Haman's name was mentioned; and I saw my revered father-in-law, the Rebbe, do likewise (in contrast to the views of the Acharonim cited in Sdei Chemed, loc. cit., sec. 10).
- (Back to text) In the light of the above, HaYom Yom, p. 37 (entry for 14 Adar II) requires emendation. [All current editions have since been updated accordingly.]
These two variant readings are cited in the works of the Masorah. Yet a primary source and a satisfactory explanation still have to be sought as to why specifically these two phrases are customarily repeated in order to satisfy all the alternative requirements.
I have encountered a quotation from the Responsa entitled Shevet Sofer (on Orach Chayim, sec. 27) that relates that the Chasam Sofer introduced the custom in his beis midrash of reading both variants, laharog and v'laharog. In his Megillah, moreover, the former word appeared as usual, with the latter word added between the lines. It is likewise reported, on the authority of Keses Sofer, that the Chasam Sofer instituted the same custom with regard to bifnehem and lifnehem. In this case, the whole word bifnehem appeared as usual, with the single letter lamed suspended between the lines.
These books are not at hand at the moment, but it would be of interest to determine whether the Chasam Sofer used to repeat only the disputed word, or whether he would repeat a phrase, as in our custom as noted in the text above.
- (Back to text) See end of the Piskei Dinim of the Tzemach Tzedek, and Shaar HaKollel, sec. 47.
- (Back to text) This practice differs from the custom cited in Mishmeres Shalom 50:4, of wearing the tefillin of Rabbeinu Tam for the daytime reading.
- (Back to text) The above wording contrasts with the version that appears in various Siddurim: Arurim kol ovdei gilulim bruchim kol yisrael "Accursed be all idolators, blessed be all of Israel." In the Tur and Shulchan Aruch, Orach Chayim 690:16, there are differences from one edition to the next, evidently on account of the censor, and if so this would seem to imply that their original version spoke of idolators and Jews, rather than of resha'im and tzaddikim. This point requires further study.
- (Back to text) These words appear in the second maamar beginning Chayav Inesh Libesumei in the [major] section on Megillas Esther in Torah Or.
- (Back to text) This sentence appears in ch. 8 of the maamar beginning Vayikach Haman in the section on Megillas Esther in the supplements (Hosafos) to Torah Or.
- (Back to text) As to the question of whether this involves an obligation to honor Purim by partaking of a formal meal including bread, the relevant opinions are set out in Magen Avraham 659:9 and in Ba'er Heitev, loc. cit. Mor U'Ketziah holds that there is such an obligation, as too does Nimukei Orach Chayim (by the author of Minchas Elazar), who cites the authority of Tosafos on Berachos 38a and 42a. On the other hand, Birkei Yosef (in sec. 695) holds that one can fulfill one's obligation without bread. It is clear that this is also the view of the Alter Rebbe, who writes in his Shulchan Aruch (sec. 187:8) and in his Siddur [p. 235] that a person who forgot to say Al HaNissim in the Grace after Meals does not return to repeat it. However, another statement in his Shulchan Aruch (sec. 188:10) is somewhat problematic: "There is...no [proper expression of] joy [at a meal] unless bread is eaten...." See there. But this is not the place for a more detailed discussion.
As to whether there is a comparable obligation to eat meat on Purim, Rambam writes (in Hilchos Megillah 2:15): "What is the nature of this obligatory festive meal? - One should eat meat, etc...." This view, however, has not been cited by the poskim as binding, as has been commented by Nimukei Orach Chayim, loc. cit.
- (Back to text) These practices are of course not intended as directives for the public.
- (Back to text) The above sentence was added by the compilers of [the Hebrew original of] this work. See Toras Shalom: Sefer HaSichos, p. 243.