Even when I was a student there, we used to enjoy riding the bike trails at Maclay Gardens. Plus, I believe FSU's music dept concerts are free to the public--my girlfriend and I used to catch some really good jazz concerts and latin dancing.
If you're into the outdoors stuff, you can find tons to do. Go explore the national forest, kayak the spring fed rivers, hiking, mountain biking at tom brown park/ or off meridian rd, etc.