March 26, 1997, a small group of people called Heaven's Gate believed that the world was going to be "cleaned" and that the only way to survive was to leave. Comet Hale-Bopp was at it's brightest and according to their leader, Marshall Applewhite, there was a spaceship following in the tail and they would be transported away from the planet. They committed suicide by eating pudding or applesauce laced with phenobarbital and chased it down with vodka. They died wearing the same black sweatsuits and Nike running shoes and with purple shrouds over their heads.
39 members of the group, including their leader, were found dead inside of the cult's headquarters. Most of the details about this group came out after their deaths including their shedding of all things human. They were instructed to let go of all of their possessions, their sexuality, family, friends and individuality. The things strikes me most is that their leader lived the same life as them which means he didn't start this cult for the money or for political reasons.
Naturally, the world didn't end at that point and Comet Hale-Bopp did give us a wonderful show here on earth (I had my telescope out for that one). Unfortunately, many people died for what turned out to be a mote of dust or a lens abberition, but I do hope that they are on a spaceship somewhere. If this cult did anything, it opened our eyes to the mindset of cults, cult members and cult leaders.