Does such a thing exist? Ive been looking for a decent one that is updated often and includes smaller venues and i cant find anything.
pollstar is pretty solid.
My town has one that includes all of the venues big or small within about a 50 mile radius. I don't know about a national one though.
last.fm has a neat thing where it shows events in your area (and gives you reccomendations to check out based on what you've listened to)