buy a 5 day City Pass for transit, and you will get unlimited rides on the El and busses. Best way to get around unless it's late at night, but even up until 10pm and you'd be fine. Plus, you can be a nice guy and give it to some new arrival at the airport on your way out. Much cheaper than paying as you go if you are going to be getting around.
The U Boat at MOSI is awesome. And for pizza, I think Gino's East is the best.