Paula Abdul [1] 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 [2] 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 . . .