The Man from Earth, 2007 Written by Jerome Bixby, directed by Richard Schenkman.

Fun fact. It seems this film beneficed from P2P file sharing, according to its producer himself: http://www.rlslog.net/piracy-isnt-that-bad-and-they-know-it/ This is another argument in favor of the freedom of sharing information.

Sequel: watch on PeerTube "The Man From Earth: Holocene" (2017) by the same authors