Watching Mike Jones in his current habitat--the opening slot of Penn & Teller's show at the Rio in Las Vegas--it's hard to avoid the obvious question: How does he do that? While Jones's right hand reels off vertiginous runs that rival the pyrotechnics of such legends as Oscar Peterson, Earl Hines, and Art Tatum, his left spins elaborate walking bass lines (at top speeds they turn into manic stride patterns) that seem less like accompaniment than a separate and completely satisfying performance. Throughout his career, Jones has found the solo-piano format ideal for his freewheeling fantasias on old standards, as documented on four albums for the Chiaroscuro label, but he's ready to try something new. Jones now works regularly in a duo, as Penn Jillette, a steadily improving amateur bassist, joins him onstage for most of each set. Jones has said that this nightly interaction has led him to rethink his approach to playing with others and enabled him, he believes, to better tailor his style to a trio setting--the context in which jazz has historically judged its pianists. Here he'll try it out with bassist Kelly Sill and drummer Tim Davis, both of whom have an admirable ability to subjugate their own egos to find the right balance within a band and can support Jones's ideas without getting in the way of his busier flights of fancy. The three worked here together last year, and the interaction obviously impressed Jones; he plans to record this weekend's sets for his next album. Friday, December 19, 9 PM, and Saturday, December 20, 8 PM, Green Mill, 4802 N. Broadway; 773-878-5552.