The Einstein Approximation

Summary
Sheldon's search for the answer to a physics problem keeps him up all night for several days and he becomes obsessed with finding the answer. One attempt in a mall ballpit has Leonard jump in and try to get Sheldon out as he pops in and out, shouting "Bazinga!". He then decides that he needs a menial job to think better because Albert Einstein came up with the Theory of Relativity while working a menial job at the Swiss Patent Office. Since the American patent office is in Washington DC, and he doesn't want to move out of Pasadena, he interviews for any menial job with the County of Los Angeles, where he is interviewed by a woman played by Yeardley Smith. Since he is tossed out, the next menial job he can think of is to work at the Cheesecake Factory with Penny. He shows up and works as a busboy and waiter, but never is actually hired. After dropping and breaking a tray of dishes, he discovers the answer to his problem, and promptly walks out, without cleaning up the mess. Meanwhile Raj, Leonard, Penny, Howard, and Bernadette all go to disco night at the roller skating rink. The guys embarrass the women with their outfits and dancing.

Title reference: Sheldon's attempt at solving his problem by working in a menial job, comparing it to Albert Einstein's discoveries made while working in Switzerland in the Patent Office.