And if you haven't found anything else to do yet this weekend, check out Taste of St. Louis! The food's not free, but the music is! Taste of St. Louis will be happening from 4-11pm on Friday, 11am-11:30pm on Saturday, and 11am-9pm on Sunday.
There's going to be two music stages (US Bank and RAC), an art village with over 100 artists (performing, visual, and musical), the Grant's Farm kid zone (open to kids of all ages!), and a "Top Chef" competition--"Iron Chef"-style!
To find your way around, check out the map showing "restaurant row" and the stages for the concerts. According to the site, there's plenty of FREE parking, but depending on when you go you may need to walk a bit. As always, the Metro is a great alternative if it works for you.