Teatro Castro Alves, Concha Acústica

The Concha Acústica (outside stage) of Castro Alves theater in Salvador is my favorite music venue in the world (seriously!). The TCA theater itself is one of the major show venues in Salvador and it attracts some of the best theater, dance and music events in town.
The outside stage hosts frequent shows by some of the canonic names of Brazilian popular music (Maria Bethania, Gilberto Gil, Caetano Veloso, etc). What makes it special, however, is the way this particular stage is constructed. At Concha Acústica, the stage is on the same level as the audience standing area, and the only thing separating the floor from stage is a 4-feet wide security channel. If you happen to be a crazed fan of any of the artists playing a show at the Concha, there is a good chance that you may get to sit on the edge of that channel, staring your favorite artist right in the eye (in a non-creepy manner, I hope).
I have honestly not seen another show venue in the world where the audience can indeed sit within 4 feet of their favorite musician without paying a small fortune for it. At the Concha Acústica, shows run anywhere from $5 to $50 (while the inside stage hosts shows by the same artists with audience sitting far away, seeing little, and paying at times over $100).
The show calendar for TCA comes out in the beginning of each month, but bigger acts are often advertised on TCA website earlier than that. If you cannot understand the portuguese on the website, check out the monster-size electronic announcement board right next to TCA. Sometimes the Concha Acústica hosts shows under the program SUA NOTA É UM SHOW - a government program where economically disadvantaged people can exchange 10 shopping receipts for the concert ticket. For those shows, you can buy a ticket from one of the informal vendors on the street a couple of hours before music starts.