I began a thread about this exact topic some time ago and listed several films, but here are a few off the top of my head:
Forgetting Sarah Marshall
Equus
Walk Hard: The Dewey Cox Story
(Somebody) and (Somebody) Make a Porno
--sorry, couldn't think of these two characters' names!
Caligula (get the special version containig the big orgy scene)
...and several others.