Episode Titles: Isotope
You are viewing a list of 1 The Big Bang Theory episode featuring "Isotope" in their title.
The Hofstadter Isotope
Season 2, Episode 20 - Aired April 13, 2009
When Penny accompanies the guys to the comic book store, she is charmed by store owner Stuart and agrees to go on a date with him. Leonard wonders why Penny has fallen for a guy who is just as geeky as he is. In an effort to improve his love life, Leonard ventures out to Ladies' Night with Howard and Raj.