Wil Wheaton

Wil Wheaton: "Big Bang Theory" will have one of its favorite guests stars on when Wil Wheaton returns to the show for a third time as "Evil Wil Wheaton" to battle Jim Parson's Sheldon. In the episode's premise, the guys camp out in a line hoping to see an anticipated movie where they run into Wheaton, while Penny and Bernadette arrange Amy's first slumber party.

Will Sheldon, who has been bested by "Evil Wil" in two previous outings, ever win against his nemisis who will cheat and stop at nothing to win? "My inclination would be no," Parsons tells USA Today. "Sheldon already wins most of the battles on the show. It's one of the charming aspects of having a Wil Wheaton who always get the better of him."

"Big Bang Theory" airs Thursday nights on CBS.