Conversation so far:
who does penny sleep with on the big bang theory
On The Roommate Transmogrification, Raj and Penny slept together.
Who's Raj on The Big Bang Theory?
Rajesh Ramayan Koothrappali, Ph.D. is a fictional character on the CBS television series The Big Bang Theory, portrayed by British Indian actor Kunal Nayyar.

Question: why did penny sleep with the character
Self-contained rewrite: Why did Penny sleep with Raj on The Big Bang Theory?