Phil (Bradley Cooper) and Stu (Ed Helms) take their soon-to-be-married buddy Doug (Justin Bartha) to Las Vegas for a wild night. Along for the ride is Doug's future brother-in-law Alan (Zach Galifianakis), who has trouble fitting in with any group. Among the items forgotten on their night to remember is the groom-to-be, who turns up missing. Now the desperate threesome must piece together the night's activities and get Doug back before the wedding. "The Hangover" is a riotous, gut-busting, laugh-filled comedy of errors. Director Todd Phillips ("Old School") keeps the gross-out humor to a minimum while centering on the consequences of a supposed drunken binge. Without giving too much away, the morning after involves a baby, a stolen police car, a missing tooth and a tiger among other things. Most of the fun is in watching Helms, Galifianakis and Cooper as hapless victims frantically searching for answers. There is a taser scene that is absolutely hysterical. None of the leads have reached stardom yet, but that could easily change on the basis of their performances here. Heather Graham is among the supporting players as Vegas beauty Jade, who helps loosen up the strait-laced Stu. Even Mike Tyson gets in on the act. This movie is getting a lot of great buzz and it is all deserved. "The Hangover" will induce headaches - from laughter.