Mitch (LUKE WILSON) has just come home to find his girlfriend, Heidi (JULIETTE LEWIS), involved in a ménage a trois. His friend Frank (WILL FERRELL) has discovered that married life to Marissa (PERREY REEVES) is crimping his bachelor style and livelihood, while their other friend and successful businessman, Beanie (VINCE VAUGHN), is facing his own midlife crisis, what with the wife, kids and domestic life.
Thus, Frank and Beanie are excited when Mitch rents a house near the local college since they see it as their refuge and retreat where they can party like they did back in their earlier, single days. To start things off with a bang, Beanie throws a huge party that's a hit with the college students. Frank ends up drunk and streaking down the street, much to chagrin of Marissa who's driving by. The next morning, Mitch wakes up in bed with Darcie (ELISHA CUTHBERT) who he later learns is an underage high school student.
Their party life is soon threatened, however, when their former classmate and the college's current dean, Gordon Pritchard (JEREMY PIVEN), decides to claim the rental house as college property. In response, Beanie decides to turn it into a fraternity house where any students and non-students can join. As that's occurring, Mitch also runs into another former classmate, Nicole (ELLEN POMPEO), who's obviously interested in him despite having a boyfriend, Mark (CRAIG KILBORN).
As the guys relive their college days, Pritchard does everything in his power to make sure the fraternity is dissolved. From that point on, the three friends do what they must to make sure their fraternity remains open so that they can continue having fun.