(MUSIC) Rock critics are as guilty of overusing the phrase "wall of guitar" as George W. Bush is of prefacing threats with premature rebukes like "make no mistake," but in the case of Mogwai's almost entirely instrumental onslaught, such a descriptor is perennially apt. Songs like "Glasgow Megasnake" (from this year's Mr. Beast release) or "Mogwai Fear Satan" (from their 2001 My Father My King EP) simply demand architecture of that scope. (Showbox, 1426 First Ave, 447-1801. 8 pm, $17.50 adv/$20 DOS, all ages.)