Saturday Night Live a.k.a. SNL is a hilarious satire TV show on NBC. The show begins at 11:30 PM Eastern Time on, you guessed it, Saturday Night. They get a celebrity, usually an actor to host the show and a famous musician to be musical guest. The show involves mostly an opening bit, where the host will often sing a song, skits with the host in them, musical performances, and the Weekend Update with Seth Meyers. People who have hosted SNL include Michael Jordan, Oprah Winfrey, Madonna, Donald Trump  Tom Hanks, Jay Leno, Steve Martin, Alec Baldwin, and Al Gore. Musical guests have included Paul McCartney, Foo Fighters, Rhianna, and Eminem. Of course, there are many, many more.
The main political components on SNL are the Weekend Update, which is basically a news program; and the skit before the Opening Monolouge. This skit is often political. Although it makes fun of both Democrats and Republicans, you get the idea that if the writers had to pick somebody to cheer for, it would be the liberals. The SNL people tend to think of everything as something to be mocked, no matter how intelligent (as in Barack Obama).