The timeless – and notorious – Green Mill was Al Capone's favorite speakeasy (a trap door behind the bar accessed tunnels for running booze and escaping the feds). Sit in one of the curved booths and feel his ghost urging you on to another martini. Local and national jazz artists perform nightly; on Sunday is the nationally acclaimed poetry slam. Cash only.
If you're around on a Friday evening, drop by at 5pm for the Flipside show, with music played on the classic Hammond B3 organ on a small stage behind the bar. FYI, Capone's designated booth is the one at the end of the bar, on the northern side – the only seat in the house that has a view of both the front and side doors.