Cabin Boy is so bad, I'm a bit surprised that it hasn't been suggested before. Starring Chris Elliott as a sheltered rich kid who ends up on a ship with hardened sailors and of course comedy is made.
I'll be honest, I've only seen it once many years ago, but it has been at the top of my bad movie list ever since. I remember Letterman has a cameo, because Elliott and writer / director Adam Resnick (Death to Smoochy) were Letterman writers. I remember Andy Richter was in there, because I was (and still am) a fan of his. But most of all I remember the talking cupcake that spits tobacco, and really do you need to hear anything else after that?
This movie is just awful and would love to hear Paul, June and Jason have a discussion about it. I was even thinking that you could probably get Andy Richter in there as the guest for some behind the scenes insight.
IMDb: http://www.imdb.com/title/tt0109361/