Finding out about this list (and this group) turned out to be a challenge :-(
The Association of Lisp User's (ALU) web site doesn't list any information about the "Lispers of Chicago."
However, there _is_ a Greater Chicago Autocad User's Group (incorporating AutoLisp) at http://www.gcaug.com/ and a North Suburban Chicago Scheme Meetup Group at http://lisp.meetup.com/41/about/ .
I've been trying to learn LISP for quite some time (started learning during the latter days of MACLISP ;-) but never quite got over the "hump" that comes in most learning curves. I think I'm just about there - and finding more than ever what joy LISP can be.
My biggest complaint with LISP and LISP learning materials in particular was this: the materials show examples of how to write programs to compute Fibonnacci numbers, or primes, or how to write a LISP interpreter.
However, they don't show you how to write a program to (for example) sort a file and write it back to disk - or to act as a terminal program - or how to interact with a SQL database - or how to read from the passwrod file. In short, anything that interacts with the outside world is ignored by such luminaries as Winston and Horn's LISP book.
I have both the first edition (using MACLISP) and the third edition (using Common LISP).
I look forward to becoming more proficient in LISP and to the next meeting of the LISP Chicago group. Since any part of Chicago is some distance for me, it matters not where - as long as I don't have to be afraid to be there after dark ;-)