Jack: Hold on, I'll check. Uh, is I. P. Freely here? Hey, everybody! I. P. Freely! [Everyone in the office laughs] Wait a minute... Listen to me, you lousy bum. When I get a hold of you, you're dead.
(Honesty I'm terrible, I know. It's a Bart Simpson prank call to Moe. But I could so imagine Charlie winding Jack up with stuff like this on quiet days.)