From what age is a child obligated in the mitzva of reading megillas ester on Purim? What age is a parent obligated to take the child to hear the megila? Should one get drunk on purim?
The age for the child’s obligation is the same age as the father’s obligation to take his child to hear the megillah on Purim (this is the age for chinuch; Rashi and Tosafos dispute whether the obligation is incumbent on the child or on the father).
For Megillah, the age is from when the child is able to follow the reading of the Megillah. This is around 7-9, but depends on each individual child. The child can hear the Megillah at home (from a kosher megillah), but it is preferable to bring him to shul.
It is worthy practice to bring a child to shul for the “experience” of the megillah, provided he does not disturb others.
Concerning getting drunk, there are different opinions among authorities, some recommending that one drink only “more than usual,” which causes one to “fall asleep,” at which stage one cannot distinguish between Haman and Mordechai. Others writing that one should actually get drunk. A person knows himself best, and if getting drunk involves halachic problems (causing offence, not davening, and so on), then the former option is the right choice.
Sources: See Tosefta (Megillah chap. 2) which mentions the obligation of Megillah even for children, and see also Yerushalmi, as cited by Tur (Orach Chaim 689). Shulchan Aruch (end of 689) writes that it is a “worthy custom” to bring children to shul, and Biur Halachah, who understands this to refer specifically to children obligated in chinuch, questions why this is only “worthy” and not obligatory, answering that perhaps the obligation can be fulfilled at home, but it is worthy to bring them to shul. Many bring slightly younger children to shul, for the experience of Megillah (this is also a possible reading of Shulchan Aruch), provided the child is old enough to remain silent and not to disturb others.
Concerning getting drunk, see Shulchan Aruch 695:2, who states simply that one must get drunk, whereas Rema adds that some recommend drinking more than usual and falling asleep. See also Beis Yosef (according to some it is forbidden to get drunk(!), and commentaries to Shulchan Aruch.