1) On the Shabbat before Purim, we read Parashat Zachor for the aliyah of maftir (the last and eighth time a congregant is called up to bless the Torah on Shabbat, which sometimes has a special reading unconnected to the Parasha just read, ed.)
Therein is recorded the mandate to:
1) remember – and never forget – that the nation of Amaleik attacked the Jewish People unprovoked following the Exodus from Ancient Egypt;
2) eradicate Amaleik; and
3) relate to our descendants that which Amaleik did.
According to some Rishonim (early commentators), it is a mitzvah d’orayta (Biblically mandated mitzvah) to read it – or hear it being read – once a year from the Torah (see note); according to otherRishonim, it is not a mitzvah d’orayta, but a mitzvah d’rabanan (Rabbinically mandated mitzvah).
Since the obligation might be a mitzvah d’orayta, even if the nearest shul (synagogue) is a great distance away, every man age 13 and older is required to go to shul to hear the reading of Parashas Zachor if feasible (see note).
There is a dispute amongst the Poskim (halakhic authorities) whether women are obligated in this mitzvah.. Since many Poskim hold that women are indeed obligated in this mitzvah, a strong minhag (custom) has developed in many (but not all) communities that women make an effort to attend shul to hear the reading of Parashas Zachor. If a woman cannot attend the reading in shul, it is advisable that she read it herself from a printed text (e.g., from a Chumash).
Children who have reached the age of chinuch (and will not disturb the reading) should be brought to shul to listen to the reading of Parashat Zachor.
2) On the Fast of Esther, Ta’anit Esther, before Minchah, the custom is to donate monies zeicherl’machatzit hashekel, as a remembrance of the half -shekel sum that each male age twenty and above was required to donate yearly when the Bait Hamikdash (Temple) stood. Communal offerings for the ensuing year would be purchased from that collection. Since the solicitation of the donations commenced in the month of Adar, we also donate the monies in the month ofAdar.
Only men are obligated in the mitzvah of zeicher l’machatzit hashekel, not women. There is a dispute amongst the Poskim at which age the obligation begins for men – 13 or 20. It is customary for men to donate for each of their sons even below the age of 13/20. While technically only men are obligated in this mitzvah, some women donate voluntarily; and some men donate on behalf of their wives and daughters. If a woman donates even once, she is obligated to donate every year; and if a man donates on behalf of a particular member of his household even once, he is obligated to donate every year on behalf of that household member – until that member moves out of his house.
There are two prevalent customs regarding the proper size of the donation for “zeicher l’machatzit hashekel” The Ashkenazic custom is to give three of the half-coin of the standard currency of the country. E.g., in America one gives three half-dollars; in Israel one gives three half NIS. Since most people do not have easy access to half-dollars, the custom is as follows: The shul puts out three half-dollar coins in the designated pushka (charity box) or equivalent. Each man puts $1.50 in the plate and takes the three half-dollar coins in exchange. He then says “zeicher l’machatzit hashekel” (see note) and places the three half-dollar coins back in the pushka.
The Sephardic custom is to give instead the actual value of 9.6-10 troy grams of pure silver, since that is the amount that was given in the times of the Temple, the Bait Hamikdash. 10 troy grams of silver is the equivalent of (the spot price of) one ounce of silver divided by 3.11. Since the price of silver fluctuates constantly, this sum also fluctuates constantly. (In recent years, the sum has been 4-10 dollars.) See note.
If one was unable to give the zeicher l’machatzit hashekelbefore Minchah on Ta’anit Esther, one should endeavor to give it before the megillah reading at night, or at least before the megillah reading on Purim day. If one was unable to give it on Purim, one should give it even after Purim, during the month of Adar. If one did not give it during the month ofAdar, perhaps one should give it even after Adar to fulfill the custom of zeicher l’machatzit hashekel.
The monies that are collected should be distributed to poor people.
 From Parashas Ki Seitzei (Devarim 25:17–19).
 Mishnah Berurah 685:16.
 Tosafos(Brachos 13a s.v. bilshon hakodesh); Rosh (Brachos 7:20). See also Be‘eir Heiteiv (Orach Chaim 685:2).
 According to the Minchas Chinuch (Mitzvah 603), while it is a mitzvah d’oraysa to read it, one fulfills that mitzvah by reading it from a printed text (e.g., from a Chumash).
 See Sefer Hachinuch (Mitzvah 603) with Minchas Chinuch.
 Shulchan Aruch O.C. 685:7. If it is not feasible for one to go to shul, one should read Parashas Zachor from a valid Sefer Torah (Torah Scroll) without a minyan (Rema O.C. 685:7), or at least from a printed text (e.g., from a Chumash); see note 4.
 See Sefer Hachinuch (Mitzvah 603) with Minchas Chinuch.
 See Halichos Bas Yisrael 22:1 with notes 1–4.
 See note 4.
 Boys, as well as girls in those locales in which the minhag is for women to hear the reading ofParashas Zachor.
 Parents are obligated in the chinuch (training) of their young children (under bar/bas-mitzvah) to perform mitzvos that the children will be obligated to perform when they become older. In general, the age of chinuch is 6-7, depending on the maturity of the child.
 Based on M.B. 689:18.
 M.B. 694:4.
 Rema O.C. 694:1.
 See Rema O.C. 694:1 and M.B. 694:5.
 M.B. 694:5.
 See Dirshu Mishnah Berurah notes to 694:5 (citing Rav Elyashiv), based on Mishnah Shekalim1:3. Cf. Koveitz Halachos, Purim page 50 regarding cases in which women donate voluntary or someone donates on their behalf.
 Some Ashkenazim are stringent and donate according to the Sephardic custom; see below in the article.
 Rema O.C. 694:1. The reason is that the word Terumah (Separation/Donation) is written three times in the section in the Torah that discusses the half- shekel obligation. See Shemos 30:11-16.
 One should be careful not to say that the sum is for machatzis hashekel lest it be considered a donation to the Bais Hamikdash (Yechaveh Da’as 1:86, based on Teshuvos Ge’onei Mizrach Uma’arav#40).
 See Piskei Teshuvos vol. 6 page 574; and Yechaveh Da’as 1:86.
 Kaf Hachayim 694:20.
 Their custom is as follows: The shul puts out three half-dollar coins in the designated pushka or equivalent. Each man pick up the three coins and exchanges it for the required sum based on the value of silver, and then returns the three half-dollar coins to the pushka. Kaf Hachayim (ibid.) writes that if there is a coin in circulation whose value is equal to or greater than the silver requirement, one who wishes to fulfill the mitzvah in the best possible manner should donate three of that coin.
 See Rema O.C. 694:1; M.B. 694:4.
 See Dirshu Mishnah Berurah note to 694:4.
 Sha’arei Teshuvah O.C. 694:2; Kitzur Shulchan Aruch 141:5; see Rema O.C. 694:1 and Sha’ar Hatziyun 694:9. Cf. Aruch HaShulchan 694:8. Kaf Hachayim (694:22) records that the custom in his country was to send the collected monies to Eretz Yisrael to be distributed among the Torah Scholars who lived there; and that the custom in Eretz Yisrael was to use the monies collected there for the upkeep of the shuls or for distribution to needy Torah scholars.