The story of two disconnected sisters summoned home to clean out their childhood bedroom before their parents sell the family house. Looking to recapture their glory days, they throw one final high-school-style party for their classmates, which turns into the cathartic rager that a bunch of ground-down adults really need.

Mac and Kelly Radner enter into a one-upmanship war their neighbors, the Delta Psi Beta fraternity led by president Teddy Sanders.

Paul is a regular guy who is engaged to marry Karen. Shortly before the wedding, Paul's friends throw him a bachelor party. Paul strikes up a conversation with one of the dancers, Becky, and the next morning, he wakes up bleary-eyed with a massive hangover -- and Becky in bed next to him. Karen comes over and Paul attempts to explain some incriminating evidence with a few white lies, but this messy situation gets messier when Paul runs into Becky...

Three middle-aged men disenchanted with their lives, try to relive their youth by moving into a house on a college campus and start hanging out with a group of misfit college students, losers, and retirees.

Doug Billings and Tracy Garner are about to get married. Two days before the wedding, Doug and his groomsmen hop into Tracy's father's Mercedes for a 24-hour stag party in Las Vegas. The morning after their arrival in Vegas, they awaken in their Caesars Palace hotel suite each with the worst hangover. No one remembers what happened in the past twelve or so hours. The suite is in shambles and Doug is missing. Phil, Stu and Alan try to find Doug using...

Seth and Evan are accepting the fact that they will be going to different colleges in the fall. Now, it seems more imporant than ever that they go to a high school party, and achieve some of their long time goals. This includes, but is not limited to, losing thier virginity with the girl of their dreams by getting them wasted and being their "regret hookup." Their awkard friend Fogell gets a fake ID, with just the name McLovin, and agrees to get liquor...