[Espy]

It's "Gee, Brain".

"Same thing we do EVERY night, Pinky. Try to take over the world."

(Actually, I've never watched a single episode of this. I only know the theme song because several years back, one of my friends pulled a few all-nighters for a Carnival project called Booth, in which a student org builds a one-to-two-story booth/house as an exhibit. When she finally finished, she was a bit... delirious... and started sitting in a corner, singing to herself.)