The way things usually work is this: Someone writes a play, which goes through several drafts, readings and workshops. Then a director holds auditions to find the right cast, who rehearse it for weeks before finally presenting it to the world on opening night. The 24-Hour Theater Project turns that procedure on its head. Here, opening night comes just one day after the whole thing begins, and the insanely condensed process itself is ass-backwards.

The play-in-a-day form is growing in popularity and, at the same time, institutional support. Northampton’s almost-annual edition goes up again on Saturday, this time under the auspices of Smith College. The Berkshire-based WAM Theatre, which first tried it on last year, has another go next month as the guest of Shakespeare & Company in Lenox. I’m a 24-Hour addict myself, having participated in several of these seat-of-the-pants affairs as director, dramaturg and, in one case, last-minute actor when one of the playwrights wrote more parts into her script than she’d been assigned.

I’d better explain. On Friday night, each of six playwrights (five in WAM’s version) draws actors at random from a pre-selected cadre of performers, then has 12 hours to write a 10-minute play for that cast. The next morning the bleary-eyed authors deliver their scripts, which are assigned to directors by lot, and the rehearsal scramble begins.

In this compressed schedule, there’s little time for analyzing character motivations and honing details. For playwrights and actors alike, it’s all about broad brushstrokes and quick decisions, and surprisingly, the pressure tends to yield intuitive choices that work. Audiences are consistently amazed that the product has been turned out in mere hours. While the teams shape their pieces, volunteers scurry after costumes and props. The day culminates in brief tech sessions for each show, a final run-through, and then, after a dinner break, it’s curtain up for the shows’ opening—and closing—night.

For the participants—playwrights, actors, directors and crew—this adventure in instant playmaking is exhilarating, terrifying and addictive. For the audience it’s like watching a high-wire act: exciting and entertaining, with the value-added possibility of disaster at every moment.

This year’s Northampton 24-Hour Project is a benefit for the Smith College theater department’s summertime tenant, New Century Theatre. Participants in the writing, acting and directing categories contain both veterans and newcomers to the experience, including the project’s founder, playwright Tanyss Martula, and NCT’s director, Sam Rush, who likens the event’s souped-up spirit to “the Iron Chef meets NASCAR.”

Next month’s outing in Lenox, borrowing the time-tested Northampton model, will involve a couple of Valley figures, including the Theater Project’s Danny Eaton. A co-production of WAM and the New York Capital Region’s MOPCO improv troupe, it’s an opportunity, according to WAM’s co-founder Kristin van Ginhoven, “for theater artists from two creative communities to come together in a full-on, adrenaline-filled collaboration.”

After previously participating in both regions’ 24-Hour efforts, I’ll be just an eager spectator this time. But I’ll be looking up at the tightrope with adrenaline flowing too.

24-Hour Theater Project:

March 24, 7 and 9 p.m., Hallie Flanagan Studio Theatre, Mendenhall Center, Smith College, Northampton, (413) 320-3147 or newcenturytheatre.org.

April 14, 8 p.m., Bernstein Theatre, Shakespeare & Company, 70 Kemble St., Lenox, (800) 838-3006 or brownpapertickets.com/event/217238.

Contact Chris Rohmann at StageStruck@crocker.com.