Ice Age: Three mammals and a baby. Also, unlucky guy tries hiding his food.
Ice Age The Meltdown: The mammals meet three even weirder mammals. The day is saved by the unlucky guy.
Ice Age Dawn Of The Dinosaurs: One of the mammals discovers fatherhood. An attempt of another to do the same leads him to need rescue. The unlucky guy meets the woman of his dreams... and leaves her behind for food.
Idiocracy: Blood Sports are used as punishments, and humans nearly go extinct from incompetence, famine and drought. It's a comedy.
Igor: A mad scientist's assistant invents something revolutionary, with the help of an immortal suicidal rabbit and a brain in a jar. His plans backfire when his invention does not turn out evil, and instead aspires to be Annie.
In Bruges: Mad-Eye Moody, Fleur Delacour and Lord Voldemort hang out in a small Belgian town with Colin Farrell and a midget. They all try to kill each other.
Alternately: Two Irish hitmen get sent by their boss on a boring sightseeing tour.
Or, Quentin Tarantino teams up with Eli Roth, Brad Pitt, and the Jewish kid from Freaks and Geeks. Their mission is to stab history in the face. With a baseball bat.
Ink: A ragtag bunch of invisible, stylish, physically fit, attractive dead people try to get a young girl to wake up after she is kidnapped by an albino with a gigantic schnoz. This can only be done if her dad stops being a Jerk Ass.
Interstellar: Astronauts embark on a decades-long quest into deep space to find a way to save humanity from extinction, but it turns out all they needed was a broken watch.
Interview with the Vampire: A dysfunctional family consists of an effete Parisian socialite, an emo former slaveowner, and an increasingly bitter "child" who kill for fun and profit. Later, two of them conflict with a theatrical group.
Queen of the Damned: A French violinist forms a rock band, pisses off all of his old friends, and gets kidnapped by an Egyptian nymphomaniac.
Or: Two children discuss the value of peace and life. Then, bigger one responds by shooting at the United States military and taking a nuclear missile to the face and being blown apart, then recovering.
Or: Someone else's hunting trip makes someone uneasy. In the climax they respond by taking a nuclear missile to the face.
Iron Man: Terrorists put an engineer in a cave with a box of spare parts. This leads the man to solve unethical business practices of his company.
OR: A rich guy goes to Asia to drink and flirt, gets a new suit, and leaves with a new enlightened outlook on life.
OR: Rich drunk with a heart condition builds flying hot-rod, races larger hot-rod.