UW's giant gym, the IMA
The IMA not only has workout equipment, but also holds classes such as yoga, Zumba, pilates, etc. It has a smoothie/food place for after workouts, a pool and hot tub, indoor track, multiple gyms, and more. You can participate in many intramural sports here at UW, club teams, and varsity sports. The IMA is always filled with people taking a class, playing a sport, or just getting a workout in. Sadly it's a far walk from my dorm on north campus, but is a great perk to being a student at UW (only students can get in!).