Phenomenon (1996) / Fenomenet (UK-import)
John Travolta plays a mechanic who sees a bright light in the sky one night and wakes up the next morning a genius, hungry for knowledge and so smart he figures out national defense secrets in his own living room (and gets in hot water for it). The more interesting drama, however, is not with the government but with the character's longtime neighbors and friends, who come to reject him for being different.