Enjoy your time at the slots, tables, or in their restaurants.
Pre-book a tour of the Old Joliet Prison
Nature walks, bird watching, fishing, picnics, kayaking, etc.
This is a bit of a drive away (about an hour or 1.5 hours from Joliet) but provides awesome hikes, canyons, and views.
The Joliet Slammers have games on both the 13th and 15th if anyone wants to snag some tickets for a nearby baseball game.
About 45 minutes by car for all Chicago has to offer.