This is a true sleazy bar in the heart of the Loop. The paint is peeling off of the walls, the mirror behind the bar (where it isn't busted out) hasn't been cleaned since before the war, their "patio furniture" is tables from the bar moved to the sidewalk, the bathroom is cleaned by a homeless man who is paid in wine (so you can imagine the quality job there), the glassware is murky and the food gives you indigestion right away.
On the upside, if you want to become a regular somewhere, it is easy here. Show up, drink, shut up and then leave. Low-key is hardly the word. The staff is no-nonsense, but friendly. And where else in the Loop can you get a beer for under $2.00.
Cal's...an experience for all who have the guts to do it.