A meteorite crashes to Earth, hitting Susan (Reese Witherspoon) on her wedding day and infecting her with a strange radiation that makes her huge. She gets apprehended by a U.S. government agency run by General W. R. Monger (Kiefer Sutherland) that has captured monsters since the 50's. The Missing Link (Will Arnett), Dr. Cockroach (Hugh Laurie), B.O.B. (Seth Rogen), and a giant mutated grub have been incarcerated there for a long time.
Susan, now named Ginormica, and the other monsters are put into action by the government when an alien spaceship lands on Earth to get the radiation from Ginormica's body. Working together the monsters manage to stop the alien ship, which turns out to be a robot, but the alien overlord running it, Gallaxhar (Rainn Wilson) decides to take a more direct hand in getting the radiation energy. Now the entire Earth is threatened and the monsters are going to have to take the fight right to the aliens...
This was the first movie I've seen in 3D and it was awesome. It was funny and ridiculous. Rogen's stoner laugh fits the blob B.O.B. perfectly and Stephen Colbert is great as the clueless President. An excellent film!