A 1970 movie by Disney. It stars a very young Kurt Russell as Dexter Riley, a college student who enjoys computers even though the school doesn't even own one. Through the generosity of A. J. Arno (Cesar Romero), the school gets a computer, and Dexter starts playing with it late at night during an electrical storm. Sure enough, he gets an electric shock for not being properly grounded and he assumes the functionality of the computer. This enables him to do well on his tests, lead the school's College Bowl-like team to victory, but not please his special lady.
Due to all of the old tech and campy 70's dialogue, this movie is an instant classic. However, for those of you with a more modern definition of "computer," a made-for-TV movie remake starring the irrepressible Kirk Cameron aired on ABC in 1995.