Things to Do In Chicago without spending a fortune

It is called GroupOn (Group + Coupon) http://groupon.thepoint.comand it offers a new local “thing to do” in Chicago everyday for a heavy discount with limited availability. If the daily deal sells out, or "tips," then everyone who signed up for the deal gets the discount. If not, no one gets the deal.
Typical deals include, but are not limited to the following:
•    Places to eat & drink (restaurants, bars)
•    Something to see (concerts, sporting events, tours)
•    Something to do (wine tasting, cooking class, dancing lessons)
•    Somewhere to stay (hotels, bed & breakfasts, ski resorts)
•    Something to buy (wine, gadgets, groceries)
•    Something to join (professional networks, gym memberships)
•    Services (pet trainers, dry cleaners, cleaning services)
•    Pampering (manicures, messages, haircuts)