Here’s a cartoon I just found that I really like: Adventure Time.
It’s on Cartoon Network. I don’t have TV, but I ended up watching it randomly at my aunt and uncle’s house, and I liked it enough to buy Season 1 from iTunes. It’s sort of Super Mario Bros. meets Dungeons & Dragons meets Ren & Stimpy. The main characters are a boy named Finn and his talking dog Jake, who possesses an elastic body and who can grow at will to giant size. Jake has the same voice as Bender from Futurama, and is a similar sort of cranky amoral goofball. They live in a magical kingdom full of grotesque characters, including an electric-guitar-playing teenage vampire girl, a rainbow/unicorn, and an ice wizard who’s always kidnapping bizarre-looking princess monsters. The plots are really random and constantly upend expectations, and the heroes often do and say completely inappropriate things. Also, I can’t imagine most kids watching half these episodes without getting nightmares. Check it out.