U.K. drum 'n' bass pioneer LTJ Bukem (aka Danny Williamson) and faithful microphone sidekick MC Conrad have been hosting their famed "Progression Sessions" club nights all over the world for the better part of a decade. With our clued-in and enthusiastic audiences, San Francisco is usually a favorite stop on their world tours, this most recent of which finds them jaunting from Serbia to Australia. Expect to hear exclusive new songs to be released on Bukem's own record label, Good Looking, a few months from now, and to be summoned to dance by MC Conrad if you happen to be holding up the wall. The duo hosts another "Progression Session" on Thursday, April 22, from 9 p.m. to 3 a.m. at Ruby Skye, 420 Mason (at Geary), S.F. Tickets are $10 in advance, $15 at the door; call 693-0777 or go to www.rubyskye.com.