Point of No Return (S04E11)

Stargate Command is contacted by a rambling individual who claims to possess full knowledge of a host of government conspiracies, from the Kennedy cover-up to CIA-sanctioned microwave harassment of Libertarian candidates. He sounds like a crackpot, someone hardly worthy of their attention — until he mentions the stargate. Gen. Hammond wants to play it safe. They need to check this guy out. Col. Jack O'Neill meets with the mystery caller, a nebbishy fellow named Martin Lloyd, who insists he is an alien and in possession of a spaceship (whose location slips his mind at the moment). O'Neill is ready to dismiss Martin as a harmless nut and head back to Cheyenne Mountain. Then a series of strange occurrences begin to suggest that maybe, just maybe, there could be some truth to Martin's story.... (Metro-Goldwyn-Mayer (MGM))