Gravity Falls is a cartoon on Disney Channel (Wait, come back! This is nothing like the other Disney Channel shows.). It tells the story of brother and sister, Dipper and Mabel Pines as they go to a town called "Gravity Falls" to visit their Great Uncle Stan for the summer. Along the way, they come across various weird and creepy encounters, often putting them in grave danger. The show is a lot darker than any other disney channel show for various reasons. For example, the show isn't afraid at all to use words like "Die" and "Kill", unlike a lot of other shows these days. Hell, sometimes characters are outright killed. (Although not violently, remember that this is still a Disney show) So yeah, let me give the basic rundown.
Mabel Pines
Mabel is the slightly older (By five minutes) twin sister of Dipper Pines. She has a very cheery, outgoing personality and is optimistic about nearly every situation no matter how bad it may seem. Has a pet pig named Waddles, who she won at a fair. She is always seen wearing a different sweater with some kind of symbol on it. Also has a tendency to tell things to die.
Dipper Pines
Dipper is Mabel's younger (by five minutes) brother. He is smarter than Mabel, and is usually the "thinker" when getting out of tough situations. He is skilled at capturing monsters and solving puzzles. He has a birthmark on his forehead shaped like the Big Dipper constellation, hence the nickname, Dipper.
Stan Pines
Referred to as "Grunkle Stan" (Short for "Great Uncle Stan") by Dipper and Mabel, Stan is (obviously) the great uncle of Dipper and Mabel and the owner of the Mystery Shack, a tourist trap that houses many fake and unconvincing "oddities". Despite this, the shack is widely popular with tourists and residents alike, and he enjoys this due to his love of money.
Common saying: "BEHOLD! ___________!"
http://www.youtube.com/watch?v=tctX771EQeA