Northwest Film Forum kicks off its 20, 30, 40: A Trio of Anniversary Concert Films series (also featuring Lasse Hallström's legendary ABBA: The Movie and D. A. Pennebaker's Dylan classic Don't Look Back) with the greatest concert film ever made that's not Stop Making Sense. On both record and celluloid, Sign o' the Times captures Prince at his all-time best, with a minimum of crappy plot elements and a maximum of rock 'n' funk 'n' roll. (Northwest Film Forum, 1515 12th Ave, 267-5380. 7 and 9:15 pm, $8.50/$6.)