NEW YORK — The first thing to know about “Freestyle Love Supreme” is that the guys onstage — who included Lin-Manuel Miranda the night I went — are having a blast.

The second is that you will, too.

“Freestyle Love Supreme” is the brainchild of Miranda, musical improv guru Anthony Veneziale and Thomas Kail, the Tony-winning director of “Hamilton.” It’s a delightfully wit-laced evening of comedy rap devised on the spot by a tight cadre of performers, backed by a pair of equally deft instrumentalists — a kind of hip-hop version of the popular comedian-stocked game show, “Whose Line Is It Anyway?”

The fast-thinking geniuses who turn audience suggestions into hilarious, rapid-fire rhyme leave you feeling happy and, yes, a little sad, too, after their 75 minutes of adrenaline-infused cavorting on the Greenwich House Theater stage. Sad because there’s so much joy attached to their collective act of spontaneous creation that you’re reluctant at the end of the show to acknowledge that yes, all good sets must come to an end.

A bottom-line hipness usually attends hip-hop, but the rotating roster of men of “Freestyle” (and gee, why not a female rapper in the mix?) seems to be imbued with hip-hop nerdiness. I note this with awe and respect, because the act they’ve constructed is as smart in its way as a bygone session with Nichols and May. (Google ’em, young people.)

The atmosphere in the packed theater Sunday night had a comedy-club vibe, aided by the energy and charm of Veneziale, the smooth operator who both raps and serves as a kind of major-domo. His confederates were these gifted fellows: Utkarsh Ambudkar (rapper name: UTK), Chris Sullivan (“Shockwave,” the sound effects rapper) and two special guests: James Monroe Iglehart (“J-Soul”), a Tony winner for playing the Genie in the musical “Aladdin” and now in “Hamilton,” and Miranda (a.k.a. Lin-Man).

On other nights, the cast can include Bill Sherman (“King Sherman”) or two other “Hamilton” alums: Christopher Jackson (“C-Jack,” who originated George Washington), or Daveed Diggs (“Mr. Diggs”), a Tony winner for his portrayals of the Marquis de Lafayette and Thomas Jefferson in “Hamilton.” (The keyboardists on Sunday were Arthur Lewis and Ian Weinberger.)

As the show is reinvented at every outing, and the performers so seamlessly transform even the most absurd ideas into rapped stories, the quality of the audience input may not matter that much. Although my audience most assuredly knew how to play — the concepts for one flight of hip-hop fancy were panty lines, tuberculosis and shaving. (A few of the other raps, of course, go to profane places.) It’s a measure of Ambudkar’s mad skills that uncannily on cue he came up with a coherent verse to incorporate the aforementioned disease — and a rhyme for it.

The range in theatergoers’ ages attested to the wide appeal for this kind of entertainment. And watching Miranda join the fray so gleefully made you realize how much pleasure he gets in putting himself on the line. In improv, there’s always a high potential for going out on a limb and having it splinter beneath you. Then again, how can you not give wholehearted support to such an ingratiating feat of linguistic daring? And as long as we’re asking questions: How can this show not swear an oath to spread its freestyle love beyond this small playhouse in Greenwich Village?

Freestyle Love Supreme, created by Thomas Kail, Lin-Manuel Miranda and Anthony Veneziale. Directed by Kail. Set, Beowulf Boritt; costumes, Lisa Zinni; lighting, Jeff Croiter; sound, Nevin Steinberg. About 75 minutes. Through March 3 at the Greenwich House Theater, 27 Barrow St., New York. All performances have sold out, but consult the website for details of a ticket lottery on some days. Recommended for age 14 and older.