I've also been watching Monkey dust, which is a very British animated show, and it's also one of the darkest shows ever. May actually be the darkest non-anime animated show ever... it's all about suicide.. and explores rape, child molestation, and so on. Like TATAMI GALAXY above, it goes deep into characters' psyche.. MONKEY DUST is intersting because each episode has about 500 different animation techniques... each episode is very very different.. worth checking out. There's a dvd with season 1 but one of the show's creators died and "out of respect" (?) they're not going to release season 2 or 3. Weird. Just d/l em .You'l be glad you did.
seems like a no brainer to show on adult swim but they don't really show dark crazy shit anymore do they?