THE HANGOVER, from writers Jon Lucas and Scott Moore and director Todd Phillips, is a buddy/road movie, full of the tangles guys can get into on legendary bachelor parties, especially in Las Vegas.  The groom (Justin Bartha) and his groomsmen (Bradley Cooper, Ed Helms, and Zach Galifianakis) drive from LA to LV in the snazzy Mercedes of the groom's prospective father-in-law (Jeffrey Tambor).  Right away you know, if you've ever been to the movies, that that car will not survive intact.  

The groomsmen awake the next morning with amnesia, a tiger in the bathroom, and a missing groom.  As their search elongates, it includes Mike Tyson in a cameo and a very naked guy in the trunk.  (Not the only naked guy, and no, none of the naked guys are the groom.)  In addition to its intended audience of junior high boys, THE HANGOVER is supposed to be drawing large female audiences because they enjoy watching how stupid guys get when they've been drunk, and the movie is funny in a nightmarish kind of way.