The Jiminy Conjecture
The Big Bang Theory Season 3 Episode 2 (09/28/09)
Leonard makes the mistake of telling Sheldon and the boys that his hookup with Penny was "fine." Sheldon, of course, doesn't realize he crossed the line when he makes a joke about the mediocre hookup to Penny. Penny gets extremely upset and Leonard goes over to talk to her and she even admits it was just okay. They decide maybe they need to try again and try and find their rhythm.
When that doesn't work with the kissing, they try again with a little peppermint schnapps, but that just puts them both in the bathroom taking turns hugging the toilet. Sheldon, continues to cross the line, when he talks to Penny outside and suggest they just go back to being friends if it doesn't work between them. Leonard heads over to Penny's to talk to her and when they decide to be just friends... instantly they're both turned on and jump each other. Hey, whatever it takes to keep this awesome couple together.
Meanwhile, Wolowitz and Sheldon make a little bet about Wolverine's bone claws and that eventually leads to a much more serious bet between the two. When the guys are eating dinner they hear a cricket and decide to bet what type it is. Wolowitz apparently was a bit of a bug collector as a kid and is willing to put one of his best comic books against Sheldon. They go to visit an entomologist at the school (played by guest star Lewis Black) and he confirms that Wolowitz was right. Woh, Sheldon was wrong on something.
The name of the episode, "The Jiminy Conjecture," comes from the name that Sheldon suggests they give the cricket. Obviously referencing Pinocchio.