Paula Abdul appeared on Letterman Monday night to promote a plethora of projects, including a song she contributed to Randy Jackson's new album. Last month, Paula and Randy teamed up to showcase their new ditty at the Super Bowl. Of course, Letterman tried to get Paula to comment on her big comeback performance, but our gal was too busy playing "opposite day" and talking like a robot to give a straight answer. This prompted Letterman to ask the burning question . . .