In its rawest form, improv comedy is fleeting. Live improv operates under the assumption that anything can happen, provided it never happens again.

That was the credo of the Washington Improv Theater’s annual Improvapalooza festival, in which local improvisers embraced their wildest ideas for a six-day marathon of short, unscripted sketches last week at The Source. Most were conceptual (an ad-libbed episode of “Downton Abbey”); some were very meta (a group pretending to be Chevy Chase Country Club wives performing improv for the first time). Some were just confusing. I do not advise improvising a murder mystery, a la “Clue.”

On Saturday, I saw the opposite end of the improvisation spectrum in the film “Drinking Buddies” (available on iTunes), a loosely outlined, mostly improvised dramedy about two brewery workers (Jake Johnson, above right, and Olivia Wilde) and their significant others. While the performers at Improvapalooza were trying for quick laughs, “Drinking Buddies” aims for something much more naturalistic (and permanent). It’s funny, but less ha-ha funny.

In both, improv is used to create something out of (almost) nothing. Sticking to the script is overrated.