Cambridge’s Lizard Lounge continues to be a cozy breeding ground for musical experimentation. Last week, the self-described "circus free-improv sextet" Beat Science began their month-long Thursday residency with special guest trombonist and composer Roswell Rudd. At the end of the evening, Beat Science leader Brian Carpenter explained to me that the band’s usual procedure is to alternate written arrangements with free improv, but the second set that I saw leaned heavily into the free.

Following Carpenter’s introduction, Rudd — an avant-garde legend for four decades — took the stage, acknowledged the applause, said offhandedly, "Looks like I’m gonna kick things off," announced, "This is from nowhere," and proceeded to wend his way through a 20-minute a cappella trombone solo that used the melody of Edward Heyman & Johnny Green’s "Out of Nowhere" (a standard for Charlie Parker) as its touchstone. Rudd also briefly quoted "Sweet Georgia Brown" and "Old Man River," scatted, declaimed nonsense syllables, walked around the stage as he played, encouraged the audience to produce an "om" tonic note that he riffed on, and unleashed shakes, trills, circus-band glissandi, some New Orleans rhythm, and several beautiful long, held notes.

Beat Science in its current form has been around only since last November, though Carpenter has been rehearsing with banjo player Brandon Seabrook and drummer Jerome Deupree for a couple of years. Last Thursday, the band formed a wide circle on stage — even Deupree’s drum set faced in from one corner. Tubist Ron Caswell started things off with an electronic rhythm from his effects-box/turntable set-up and the band joined in long tuning-up tones. There was a break and some fast, stuttering figures from Seabrook’s banjo, then another free horn passage; Deupree moved in and out of boppish swing; and so on. At times the band coalesced for an exultant minor-key klezmer melody over a tango rhythm. Caswell played a walking-bass line and falsetto high free passages. There were solo statements from everybody, including a piercing, over-miked passage from altoist James Merenda; there was loud, bouzouki-like speed banjo from Seabrook, Charlie Kohlhase’s warm, warbling baritone sax, and a frenetic duet passage between Rudd and Seabrook. Rudd signaled with broad arm and hand gestures, funny faces, and a waggling tongue. When it was time for an encore, the trombonist called out, "Let’s play some Dixieland." And so they did.

(The Beat Science residency at the Lizard continues tonight, June 12, with guests Spanish Fly and Kleztraphobix; call 617-547-0759.)