Gawd what useless answers from you all.
1. Take in a play (8pm Fri or Sat) at the Broom St. Theater on Williamson St. Sometimes funny, sometimes bad, sometimes good but cheap and entertaining.
2. Capitol building tour
3. Take in the sunset at picnic point
4. Beer, popcorn and/or ice cream on the Memorial Union Terrace.
5. Cruise up and down State St; have a coffee; poke around shops; etc.
6. Vilas Zoo is free and fun for the kids
7. Catch a Cycropia aerial dance show (cycropia.org)
8. Meet the locals at the Harmony Bar for great food and music
9. Any of the following street or other festivals: Atwood, Willy St., Marquette Waterfront, Fete de Marquette, Orton Park, solstice bonfires
10. Rent a bike and bike around Lake Monona
11. Rent a canoe at the Memorial Union and go for a paddle on Mendota
12. Capitol farmer's market (duh)
Do not under any circumstances visit anything not a farm or state park further than 3 miles from the capitol building (such as Fitchburg).