In the summer of 1964, “One Flew Over the Cuckoo’s Nest” novelist Ken Kesey and a dozen friends and hangerson piled into an old school bus and journeyed from the hills of Northern California to the World’s Fair in New York City. Along the way, the “Merry Pranksters,” as they called themselves, took LSD, had sex, danced by roadsides and took more LSD.

That infamous trek is the subject of “Magic Trip,” a documentary screening tonight at the Oklahoma City Museum of Art. It’s surely required viewing for anyone fascinated by that merry band who was elevated to counterculture mythology in Tom Wolfe’s “The Electric Kool-Aid Acid Test.” The uninitiated might be less enthralled. Regardless of what you know about hallucinogens, it’s probably fair to say that being on an acid trip is a lot more interesting than watching others be on one.

Still, you’ve got to give credit to Oscar-winning documentarian Alex Gibney (“Client 9”) and his co-director, Alison Ellwood. The pair salvaged and gave shape to copious 16-mm footage the Pranksters had filmed of their crosscountry drive in a psychedelically painted bus. This was not an easy task, as Kesey and company didn’t really know how to use the cameras they had brought. Gibney and Elwood cleverly employ a mix of archival interviews and voice actors to remedy the problem of the home movies being without synchronous sound.

The effort is impressive. Whether it was worth it is another matter. It’s a kick to see the color footage of Neal Cassady, the basis for the Dean Moriarty character in Jack Kerouac’s “On the Road.” Cassady, a speed-popping motormouth, was the Pranksters’ self-appointed bus driver. Other icons of that freewheeling period — Kerouac, Allen Ginsberg, Timothy Leary and Ram Dass — make fleeting appearances.

“Magic Trip” boasts at least one spectacular sequence. The filmmakers have unearthed tape recordings of Kesey, who’d been part of the notorious LSD experiments at Stanford University, describing in real time his experience on the drug.

Visualized through the animation of the Imaginary Forces studio, the vignette captures something vital and a bit naive about that time — something you can’t get just by hopping on a psychedelically painted school bus.

Photo by Ted Streshinsky Corbis