The Big C Season 1 Episode 8 (The Big C s01e08) with title “Happy Birthday, Cancer” aired on Monday, October 11th 2010 at 10:30 pm via Showtime Network.
Here is summary for The Big C Season 1 Episode 8 :

Lenny invites Cathy to the Bahamas for an art opening to celebrate her birthday, but Paul throws Cathy a surprise party and invites her flaky college friend, Rebecca.