By now, you've probably seen that Call of Duty: Black Ops ad featuring Kobe Bryant, Jimmy Kimmel, and "Gimme Shelter," but the game itself contains two more celebrity guest stars: noted zombie slayers Richard M. Nixon and John F. Kennedy.

Here's a composite clip G4TV put together to show off some of the ex-presidential gameplay:

PS3 Games - E3 2011 - Call of Duty: Black Ops