Mayfest | StarEvents is THE TOP CHICAGO EVENT and CHICAGO FESTIVAL COMPANY
Here's a link describing the mid-May street festival........I think it's the first one of the year, so a nice weekend will bring Chicagoans out in force after another normal (brutal) winter.
I agree with previous posters' advice on doing the architectural cruise, Millenium Park, and the Wicker Park blue line corner on a warm weekend night is always a good time.
Welcome & enjoy!