Admit it, you still know all the words to the Bee Gee’s soundtrack for “Saturday Night Fever,” the film that launched disco, the white three-piece polyester suit and the movie career (phase one) of John Travolta. Sing along when the retro classic returns for a Friday, July 19 screening and disco party, a benefit for Sonoma’s Relay For Life. $20. 6 to 10 p.m. Moose Lodge. 20580 Broadway.