Adventure Time is a short cartoon produced by the team at Frederator Studios, the people that brought you Oh Yeah! Cartoons and subsequently spawned Chalkzone, The Fairly Oddparents, Cow and Chicken, Powerpuff Girls, My Life as a Teenage Robot among many others.
They also have a cartoon podcast that updates weekly at
Channel Frederator, which has various user submitted cartoon shorts, that is more than worth a mention.
I haven't enjoyed cartoons this much since the Fox Kids era.
I quite like this cartoon's music as well. For example, there's a cool tune with a nice GameBoy feel to it between 5:15 - 5:25. This really needs to be turned into a series.