Definitive Jux founder Jaime Meline, who goes by El-P, has spent the millennium battering hip-hop's boundaries, and on his first solo CD since 2002, he takes things well beyond his previous extremes. The results are intriguing but self-consciously arty, engaging the brain more often than they move the body. El-P throws down the gauntlet via "Tasmanian Pain Coaster," a collaboration with the Mars Volta that throbs rather than flows, and "Smithereens (Stop Cryin')," whose backing track lurches like a World's Strongest Man competitor lugging a Toyota carcass. If such material resists providing typical rap pleasures, it usually works as drama—and El-P deserves props for not allowing guests Trent Reznor and Chan Marshall to subvert his mission on "Flyentology" and "Poisenville Kids No Wins/Reprise (This Must Be Our Time)," respectively. Still, he's better when he balances ambition and accessibility, as on the propulsive "Up All Night," in which he declares, "I might have been born yesterday, sir/But I stayed up all night." At moments like these, it's worth getting some Sleep.