Twelve years is an unheard-of span of time for a hip-hop group to stay popular, and the reasons De La Soul has carried it off are loud and clear on its sixth album. The lyrics are funny but humane, the beats fresh and surprising. The high point comes when Slick Rick, one of rap's best dirty storytellers, weds his sleaze appeal to the group's nerdy humor and stuffs a Ben Stiller movie's worth of innuendo into a 5-min. track. The crackling originality that producer Prince Paul brought to the group's early work is sorely missed, but may they keep rolling on anyhow.