I'm pretty sure I've seen every episode of Adventure Time...multiple times. And I'd probably describe the animated series as a completely random, stream of consciousness cartoon. It's still very popular.
And Funko is getting in on the game (they did previously release characters in their POP! Vinyl series) by revealing the Adventure Time Mystery Minis Series. Each 2.5" tall Mystery Mini figure will come in an embossed collector tin. Keep an eye out as you'll be able to pick them up in May 2014.