You've got some good suggestions from Phipps and littlechi92.
"the viagra triangle", priceless!

I always have fun at National 27, good fun latin atmosphere, mojitos are great and the food is good to terrific, can't help but get in a great mood with that music playing.

Avec while not cheap is some one of the best restaurants going now in Chicago and is way cool as metioned for it's communal atmosphere, so if Mr. Excitement is not that exciting you'll have easy friends to make while there.
Review of Avec here: http://www.flyertalk.com/forum/showthread.php?t=363329