Gravity Falls is a cartoon that deals with discovering and dealing with the mystical and supernatural, in an otherwise mundane world. Due to this it's commonly referred to as a comedy cartoon equivalent of Twin Peaks.
The show centers around the twins Dipper and Mabel Pines, who have been sent to spend the summer at their grand-uncle Stan's place in Gravity Falls, Oregon. They soon find out that Gravity Falls is home to many monsters and supernatural events.
The show has some of the most gorgeous graphics and animation, and some of the best music I've seen and heard. The writing is also very clever, and possibly the best I've seen in any cartoon.
But seriously, you should just watch the trailer and see if it interests you.
The show has Alex Hirsch as the Executive Producer. He's previously made the shows "The Marvelous Misadventures of Flapjack" and "Fish Hooks" (Admittedly, not a very promising track record), though this show isn't like either of those. Alex Hirsch is also an excellent voice actor, and does the voice of two of the main characters. Some other important voice actors are Kristen Schaal and Jason Ritter.
The show also has Rob Renzetti as as the Supervising Producer. Now that guy is pretty much the best Director/Producer in the business, in my personal opinion. He's previously worked on shows like "Dexter's Laboratory", "My Life as a Teenage Robot" and "My Little Pony: Friendship Is Magic", among many.
The show can be found on iTunes, where the first episode is free, and the rest cost $3 each. Of course, you can also find the show on TV, and other places.
Oh, it's also very very gif-able :3
The hotspots for Gravity Falls stuff appear to be various tumblr blogs, and and possibly some threads on 4chan's /co/ forums, though honestly I don't really know =/
Kieran Edit: Links removed.