The great promise of jazz–as a creative ferment where anything and everything is possible–is rarely fulfilled by those who claim to play the music these days, be they neoboppers running through the same old scale patterns or free improvisers recycling pet licks. Dutch pianist Misha Mengelberg, one of the few musicians who still seem genuinely interested in exploiting the full potential of jazz’s bastard beginnings, heads a loose ensemble he calls the ICP (or Instant Composers Pool) Orchestra, and it makes some of the most exhilarating, surprising, beautiful, and downright joyful music I’ve ever heard. On the ICP’s new Jubilee Varia (Hatology), stylistic boundaries are dissolved like a spoonful of sugar in a gallon of coffee; the group moves unfettered from composed material to pure improvisation, from small-group passages to blustery orchestral phrases, from gently refined statements to vulgar comedic blurts, from elegant and memorable melodies to jarring cacophony. Although Mengelberg’s wondrous compositions and arrangements–the latter usually sketched out just prior to performance–would make most jazzers green with envy, the ICP rarely plays any of them straight through and never does one the same way twice. Mengelberg likes to force musicians into uncomfortable situations or, as he explained to writer Kevin Whitehead in his book New Dutch Swing, “I am interested in that; to put sticks into the spokes of all wheels.” His willful sabotage obviously disrupts the flow, but with the stellar cast of highly intuitive musicians–for this gig it’s drummer Han Bennink, reedists Michael Moore and Ab Baars, trumpeter Thomas Heberer, trombonist Wolter Wierbos, cellist Tristan Honsinger, and bassist Ernst Glerum–the music rarely falters. They use a variety of devices to keep the ideas coming, from having one member conduct others to allowing any member to inject a “virus”–a prewritten snippet intended to “infect or disable” a tune–at any time, but a listener needn’t completely understand the means to appreciate the end. This is a Chicago debut for the project, which has been going in some form or another since 1977. Sunday, 3 PM, Preston Bradley Hall, Chicago Cultural Center, 78 E. Washington; 312-744-7094. Peter Margasak

Art accompanying story in printed newspaper (not available in this archive): photo/Francescal Patella.