Stargate Atlantis: Season 3, Episode 15

3 - 15: The Game

Major Lorne discovers a planet with dozens of satellites in geosynchronous orbit. However, inhabitants on this planet are no further advanced than being themselves in a renaissance period and even stranger, he discovers a flag bearing Rodney McKay's likeness. Informing Rodney and Lt. Col. Sheppard of this, the team realize a game they had found years earlier on Atlantis might actually be much more than just a game.