There are some areas to avoid in North Denver near Regis, so walking anywhere that is a bit of a distance is not recommended. But, overall, the city is a diverse area with great activities, all within a close distance to downtown. Check out any of the bars, theaters, and museums in the heart of Denver and don't forget about the Rocky Mountains! Downtown Denver can be a lot of fun, and you can check out the Nuggets, Rockies, Broncos, or Avalanche.
Denver always has events and activities going on throughout the school year. If you are 21 and want to go to the bars downtown, a cab ride from the University is about $15, which isn't too bad. The downtown atmosphere is exhilarating and lively, especially on the 16th Street Mall, which has lots of restaurants and stores.