Sure, there's getting the bridal and grooms parties kitted out, organising the flowers, and making sure you juggle the guests so certain...
The Hangover
Las Vegas is a top location for most Stag nights, with four out of five venturing to the gambling mecca to celebrate one last night of freedom. The Hangover takes the Stag night aftermath to the extreme, with the actual party being a very, very distant memory. Though, with tigers, gangsters, trashed hotel rooms, and Mike Tyson thrown into the mix, you just know a good, albeit messy, night was had.
Bachelorette

Friends top most of a Hen's guest list, though thankfully they aren't as mean spirited as the friends of the bride in Bachelorette. With the guest of honour leaving her own party, the festivities continued, resulting in the ultimate nightmare situation: the dress getting destroyed. At least the entire house wasn't destroyed. Needless to say, the festivities ended then and there.
Very Bad Things
Strippers seem to be a Hen and Stag night tradition, but the end result is never as extreme as Very Bad Things. The crazy Stag antics get even crazier, when an accident results in a dead stripper in need of getting rid of. Things further get out of control, leading to two bodies being buried in the desert, which, thankfully, isn't a tradition.