There are 10 or so decent bars in the area, most of which are within reasonable walking distance if you live anywhere near the school. Starbusters is probably the best of the bunch because of its capacity, frequent live music, and beer garden. Molly's, Fatty's, and Lord Stanley's are also popular. Local bar owners have been hit hard with citations and fines in recent years for allowing underage drinking, so fake IDs aren't effective or recommended. If you're under 21 and unwilling to commit fraud, your options are pretty sparse, with the House Café serving as DeKalb's haven for minors.
Bottom line: If you are looking for an exotic club-going lifestyle, don't come to NIU-or else be prepared to make the hour-and-a-half trek down I-88 to Chicago every weekend. Otherwise, there are a variety of bars and on-campus parties to fill up your Thursday, Friday, and Saturday nights with. Sunday through Wednesday? That's probably asking too much out of this quiet farm town.