Let's face it, people -- categories are becoming useless. The so-called jam-band crowd has been among the first to embrace this. The Slip may appropriately be compared to the Flecktones and String Cheese Incident, but like those acts, this band is too distinct for easy references or a homogenous following. And though the Slip is also a fixture on jazz-festival lineups, the jazz influence that forms the foundation of its sound is submerged compared with the styles the band incorporates more obviously. Funk instincts are worn on the sleeve, but the Slip manages to avoid obtuse, herky-jerky rhythms. In fact, restraint is one of this band's selling points. Lots of acts jump genres freely, but the Slip serves up a smooth funk-roots-world beat (with a dash of indie rock) that's as easy to swallow as it is impressive to watch.