There's a reason Vince Vaughn enthusiastically shouts, "VEGAS BABY, VEGAS !!" on that Swingers poster I had in college: because crazy things are always happening there in movies. If it isn't Ashton Kutcher and Cameron Diaz marrying, it's a giant toddler that Rick Moranis accidentally enlarged (legitimately crazy). What a town, right? And now we can add Bradley Cooper, Ed Helms, and Zach Galifianakis losing a groom and a tooth (while gaining a standard-size baby) to that list of fictional craziness happening in Vegas with this trailer for The Hangover. Maybe not as wild as a Flintstones in Viva Rock Vegas (ostensibly a prehistoric version of Las Vegas), but it looks pretty good.