The Spotted Cat on Frenchmen Street is a real Blues bar, although it does feature other types of music. It gives that sense nothing has been touched or moved for years...and it probably hasn't!
It has wood floors and dark brown walls covered with vivid Munch-like paintings that contrast with its dingy atmosphere. Walk in past and in front of the stage where cramped musicians huddle to play for tips and a generally small audience, sitting on bar stools or on an old couch.
I like to go on Sunday afternoons to hear Rites of Swing. The atmosphere is less dingy with the afternoon sun streaming through the open door. There's no cover charge ever, but on Sundays they serve food - usually gumbo or jambalaya - for a donation.
Mississippi Slim was right at home one afternoon when I visited. I bet he has sung in many bars just like the Cat in the Mississippi Delta.