At a house party last weekend, local DJ RBI popped in and took an impromptu turn at bat. After a moment of contemplative crate digging, the woolly-haired turntablist selected a gem: the remix of Das Efx’s “Hard Like a Criminal.” On this sleeper hit, DJ demigod Premier reworked a Lou Donaldson sample into a frenetic sonic missile that torpedoes Notorious B.I.G.’s lazy “One More Chance,” based on the same loop. In fewer than 20 years, hiphop has amassed an arsenal of such classic material that—thanks to an infusion of unschooled youth—is already fading into obscurity. For dedicated heads, weekly spots like RBI’s “Underground Railroad Station” are as much a history lesson as a party. Wednesdays at 8 p.m. at La Cueva, 2224 18th St. NW. $5. (202) 234-6995. (Neil Drumming)