I remember my sophomore year in high school reading in the paper about the massacre in Jonestown. Even at that age and in that time, it was bizarre turn of events, and the easiest way to deal with it was to make jokes about Kool-Aid.
American Experience had an excellent documentary with a huge amount of new footage, both Super 8 and video, plus the audio recordings made during the mass "suicide" (really a mass murder), and many first-hand accounts of what it was like to be a member of the church. It's truly fascinating viewing, and very moving. It's hard to imagine what it must have taken to be a part of the church, and to commit a ritual suicide or murder, but this movies makes those people much more human and sympathetic than the psychotic automatons one might imagine.
Definitely worth watching, although difficult viewing.