Episode Titles: Permeability
You are viewing a list of 1 The Big Bang Theory episode featuring "Permeability" in their title.
Season 2, Episode 14 - The Financial Permeability
Aired February 2, 2009
When Penny faces financial problems, Sheldon is more than happy to lend her some money. Although Sheldon is a surprisingly reasonable lender, Penny feels uncomfortable owing him money. After Penny explains the source of her money worries to Leonard, he and the guys confront Penny's hulking ex-boyfriend, Kurt.