Frankly, it's like we discussed in the Ghostbusters commentary: a good comedy is a drama with jokes. Which means that you're looking at following classic structure in many cases -- just, with jokes.
Name any comedy that isn't a spoof and I'd say there's a 90% chance you can make a case for the hero's journey. Hell, if we're allowing spoofs -- Spaceballs was mentioned above -- most of those too, since they're probably based on a movie that you can apply the hero's journey to. This is not counting the worthless "spoof" movies of the last five years, which were just a series of other movies' trailer shots with poop added.
Ghostbusters; The Princess Bride; Stripes; Animal House; Honey, I Shrunk the Kids; Austin Powers: International Man of Mystery; Shaun of the Dead; School of Rock; Planes, Trains, and Automobiles; Bruce Almighty; Shrek; Men in Black; Bill and Ted's Excellent Adventure; Team America: World Police; There's Something About Mary; Liar, Liar; Home Alone; Wayne's World; Zombieland...
Et cetera.