The Big Bang Theory Season 2 Episode 8
The Lizard-Spock Expansion
Wolowitz thinks he's found his soul mate, Dr. Stephanie Barnett (Sara Rue), until she meets Leonard. Wolowitz lets Stephanie drive the Mars rover, which gets stuck in a ditch. He tries to hide the evidence of what they did by destroying all security tapes and hard drives related to the mission.
Leonard has a tough time breaking to Wolowitz the news that he is dating Stephanie. Leonard goes to his house to tell him in person, but while there, Stephanie breaks the news to him over the phone. Wolowitz is pissed at Leonard (you're dead to me), until Stephanie invites him on a double date.
At the end of the episode, Wolowitz hears on the TV that the Mars Rover discovered life at the bottom of the ditch but is unable to give credit as all evidence is gone.