Go to German Village and make sure to see Schiller Park. There are plenty of places to have lunch or dinner in German Village area.
There is a really nice "farmer's" market pretty much right next to the convention center. It has all kinds of different places to eat in it. The Vietnamese place was pretty good. Also as I recall an Indian place, an Italian place, etc. There are also all kinds of cute little restaurants immediately north of the Convention Center. Have fun!
My husband and I will be there this weekend and have Saturday afternoon and Sunday morning free. Looking for ideas/recommendations.