Stealing the Afikoman
One of the more popular customs of the seder is for children to “steal” the afikoman, hide it, and to later ransom it for a handsome profit. The afikoman, of course, is the matza that is eaten at the end of the seder that recalls the korban Pesach. The source for this custom is somewhat unclear and it also appears to contradict the halacha that it is forbidden to steal something even if one intends to return it, and even as a joke. Indeed, some authorities argue that this custom is baseless, foolish, and should be terminated. It is also noted that it could appear to the non-Jewish community that Jews teach their children to steal and that doing so might sometimes be acceptable. As such, there are a number of communities in which the custom of stealing the afikoman is not practiced. Other authorities hold that only children should participate in "stealing" the afikoman, while adults should refrain from associating themselves with anything resembling theft, including this.
There is a popular theory that the custom of stealing the afikoman is based on a Talmudic passage which reads, “We grab the matza on Pesach night so that the children will not sleep.” However, most commentators maintain that this passage is either referring to the customary movements of the seder plate during the course of the seder, a requirement to finish the seder before the children fall asleep, or to ensure that the children don’t eat too much matza which might cause them to fall asleep sooner than desired. There is also an interpretation that "we grab the matza…" refers to the matza that is eaten for the first time at the seder when we fulfill the mitzva of eating matza. According to this approach, although it is generally proper to wait for one's host to eat before eating oneself, on Pesach night it is permitted to disregard this courtesy and "grab" one's matza even before the host has eaten his.
There are a number of historical and textual clues that shed some light on the custom of stealing the afikoman. One of the requirements of the seder is for the leader of the seder to break the middle matza, half of which is then designated as the afikoman. The afikoman is then wrapped in some sort of cloth in order to recall that the Jewish people wrapped and carried their dough in their clothes when they left Egypt. The leader must put this broken piece of matza in a safe place in order to ensure that it is not lost or accidentally eaten before it is needed. Perhaps the requirement to keep the afikoman in a “safe place” tempted children to try and uncover their parents’ secret hiding places, and hence, afikoman hide-and-seek was born. In some communities, the custom was to give the afikoman matza to a designated person who was responsible for its safekeeping, which might also be where the custom for the afikoman to change hands originated. It might just be that children wanted to have some mischievous fun at the seder by “stealing” the afikoman when the one guarding it became distracted. They were then able to earn themselves some ransom money or other booty when it became discovered that the afikoman was missing. Alternatively, perhaps it was the children who were these appointed guardians in the first place and they simply took advantage of the situation by demanding a ransom in return for the afikoman.
It is also taught that stealing of the afikoman serves to recall that dogs did not bark on the night of the Exodus. Since the dogs did not bark, they did not fulfill their duty of guarding people’s homes and scaring away burglars. Indeed, we are told that much theft, looting, and ransacking took place that night. Hence, we “steal” the afikoman to recall that the night of the Exodus was also a night of widespread theft. Finally, it is suggested that the custom may have originated with the Rambam who writes, "We must make unusual changes on the Seder night so that the children will see and ask what is happening… for example, people should grab the matzot from one another’s hands…”
It is interesting to note that the custom of stealing the afikoman is not mentioned in the Shulchan Aruch among the many other seder customs and rituals. Nevertheless, there have been authorities throughout the ages who have justified and even encouraged the practice. It is explained that this form of "stealing" is well known and anticipated and therefore it poses no concern that anyone would be suspected of deception or malice. In any event, one is not permitted to abolish this or any other custom that has been passed down from one's ancestors, as all customs derive from hallowed sources. This “afikoman game” is also an easy incentive for encouraging children to remain awake for most of the seder. On a related note, during Sukkot in the Beit Hamikdash it was customary for adults to play a game with children in which the adults would try to snatch the children’s lulavim and etrogim.
 In other families, the Afikoman is first hidden by the head of the household and then the children are charged with finding it. Once the children find it they hold it for ransom. There are other variations of this custom, as well.
 CM 359:1.
 CM 348:1.
 Orchot Chaim 473.
 Orchot Chaim 19, cited in Minhag Yisrael Torah, OC 473:16.
 Piskei Teshuvot 473 footnote 148. See also Mishne Halachot 11:393.
 See Aseh Lecha Rav 6:36.
 Pesachim 109a.
 See OC 472:1.
 Rashi, Rashbam, Pesachim 109a.
 Berachot 47a; Rambam, Hilchot Berachot 7:5.
 Haggadat Brisk, Kovetz Hosafot p. 75.
 Shemot 12:34; Tur, OC 473. See also Vayaged Moshe 18:7; Rivevot Ephraim 8:200:5.
 Tur, Bach, OC 473.
 See Likutei Maharich and Rivevot Ephraim 8:200:5.
 Minhag Yisrael Torah, OC 473:16.
 Rambam, Hilchot Chametz Umatza 7:3; Chok Yaakov (Bechofen) 472:2.
 Cf. OC 473:6.
 Chok Yaakov 472; Be'er Heitev, OC 473:19. See Aseh Lecha Rav 6:35.
 Shana B'shana 5744 p.144.
 Noheg K'tzon Yosef, Leil Haseder.
 Sukka 45a.