Pianist Misha Mengelberg, the leader of this ten-piece dadaist powerhouse, plays some Monkish chords on his recent solo album Senne Sing Song (Tzadik) that lag so far behind the beat you could tie them to the rhythm section like tin cans to the bumper of a wedding limo. The 70-year-old Dutchman is anything but lazy, though–he’s a backseat driver for sure, but he directs the music with perverse rigor, always frustrating its natural course. It takes fortitude to play with a guy like that, and the ICP Orchestra is full of musicians so strong willed and creative that they’re not only able to deal with his contrary ways but positively thrive on them. First among equals is drummer Han Bennink, an explosive prankster who’s been playing with Mengelberg for more than 40 years. Bennink is equally at home swinging a shuffle groove on a Hoagy Carmichael tune or bashing out arrhythmic noise with punk rockers the Ex, and he and Mengelberg are constantly trying to undercut or overwhelm each other. The rest of the lineup breaks down into three reedists, a trumpeter and trombonist, and a string section of bass, cello, and violin or viola; each of these three subsets can work as a disciplined unit to define the direction of a tune or form an alliance with another faction to overthrow the status quo. The upshot of all this internecine intrigue is a group that ping-pongs deftly from genteel chamber music to Ellingtonian blues poems to squalling free-for-alls. In addition to its HotHouse set tonight, the ICP Orchestra plays Sunday at the Chicago Cultural Center and then joins a jam session later that evening at the Hungry Brain; see separate Treatment item for details. The principals also play solo sets, Bennink today and Mengelberg on Sunday. Sat 4/1, Han Bennink solo set: 5 PM, Intuit, 756 N. Milwaukee, 312-243-9088, $10. All ages. ICP Orchestra: 7 PM, HotHouse, 31 E. Balbo, 312-362-9707, $12 in advance and for students, $15 at the door.

See Saturday. Pianist and bandleader Misha Mengelberg plays a solo show this afternoon, and after a full set of its own in the early evening, the ICP Orchestra hops across town to participate in a late jam session with several Chicago improvisers at the Hungry Brain. Sun 4/2, Misha Mengelberg solo set: 3 PM, Claudia Cassidy Theater, Chicago Cultural Center, 78 E. Washington, 312-744-6630. Free. All ages. ICP Orchestra: 7 PM, Preston Bradley Hall, Chicago Cultural Center, 78 E. Washington, 312-744-6630. Free. All ages. Jam session: 10 PM, Hungry Brain, 2319 W. Belmont, 773-935-2118, donation requested.