Panera Bread, 501 S. State St (at E. Congress Pkwy) in Chicago. The closest "L" stations are Harrison on the red line, Jackson on the blue line, and Library on the pink, brown and purple lines; it is across the street from Harold Washington Library. There are affordable parking lots and also metered street parking in the area. We usually seat at a big table by the back area of the place, close to the back door.
Whereas there is no fee for participating, a $5 minimum purchase at the venue is recommended (let's keep the venue happy!)