CBS

Season 3: Episode 23 - The Lunar Excitation

The Lunar Excitation: Raj and Howard sign Sheldon up for online dating, and find the perfect woman for him. She is the female version of Sheldon (played by Mayim Bialik). Penny shows up at Leonard's door, drunk and lonely, and takes him straight into the bedroom. Leonard wakes up the next morning overjoyed until he finds out that Penny regrets the drunken encounter. Leonard decided he is going to try the same approach, and goes to the home of Leslie Winkle, (played by Sarah Gilbert). he attempts to have casual sex with her, and she shuts the door in his face.