(MUSIC) Live-rock truism #32: You can judge the impact of a performance by watching the exiting audience. Grand Champeen (arguable heirs to the legacies of Superchunk and the Replacements) played the Tractor a couple of years ago, and I was dumb enough to show up just as they were finishing. It was apparent by all the incredulous head shaking and wide-eyed raving that I had seriously missed out. Don't make the same mistake. (Sunset Tavern, 5433 Ballard Ave, 784-4880. 9 pm, $8 adv/$10 DOS, 21+.)