Gravity Falls is one of the best things on TV right now. It just finished its first season, with intermittent shorts tiding over until season two begins late in 2014. Damn. Anyway, it has Kristen Schaal and Chris Parnell in it, making it one step away from being a 30 Rock reunion. Also, the guy who wrote the Homestar Runner cartoons writes on it as well. I wholeheartedly suggest y'all check it out.
As the others mentioned, it's the latter, but it's on a classic Simpsons level on quotability. Girl, why you ackin' so cray cray?
The latter. It's pretty cool though, and the art's really good.
I saw an episode once on a plane while there was nothing else on, definitely seemed to be more of an 'adventure time' kids show, drawing adults. mainly geared toward children with some things thrown in for adults as well