There are no parties on campus. They're mostly held Thursday through Sunday in houses around the neighborhood. Parties are plenty of fun, but once you turn 21, being downtown is a blast; thus, most 21-and-up students spend a majority of their time in downtown Denver. In addition to Denver, Boulder, home of the University of Colorado, is about 30 minutes away, so some students will go there to party, as well.
The house parties that go on around Regis are a lot of fun, since there is a diverse range of personalities, and they all come together at a Regis party. Everyone gets along and is very welcoming, so if you don't know the host of the party you attend, you will soon. Downtown Denver has a great atmosphere, and taxis are readily available to get you home after your pleasant night out. Boulder is a bit of a drive, but once you get there, it's a great time!