By far, the leading klezmer band in Chicago for the last 20 years has been the Maxwell Stree Klezmer band.

I have seen this fabulous group of musicians/entertainers numberous times and own a few of their CDs.

Their web site is:

http://www.klezmerband.com/

Art Thieme, I believe separate but equal.

My grandfather came from Russia in the late 1910s and was a klezmer clarinet player bringing the music over with him like many others. The west side of Chicago had a wealth of this music playing in halls every weekend. My mother told me he was quite active playing for weddings and other simchas.