Check out Hafenkneipe for the best concerts in the tiniest of bars (
http://www.hafenkneipe-zh.ch). I love it there (but it's really tiny, I warned you!). Also good are El Lokal (
http://www.ellokal.ch/), Mascotte (mascotte.ch) and Abart (abart.ch).
Here's a good list of upcoming concerts (gotta filter for zurich manually) ->
http://www.starticket.ch/0showlist.a...O---&OrderBy=5