Official 3rd (Artrock, c. 1990) printing 18 x 22&7/8" silkscreen event poster, "Can You Pass the Acid Test?", Ken Kesey and the Merry Pranksters' legendary series of LSD-fueled multi-media happenings/parties held up and down the West Coast from November 1965 through October 1966.

 "Happeners" (participants/acts) listed on the poster include: the Fugs, Allen Ginsberg, the aforementioned Merry Pranksters, Neal Cassady, the Grateful Dead and "Roy's Audioptics" (Prankster Roy Seburn's light show).

 Art by Paul Foster (sometimes mis-credited to Norman Hartweg), image (a 1980's-era Prankster-created version hand-colored by Sunshine Kesey) is featured in the Art of Rock book on page 91 (plate 2.4); this particular version was created around 1990 and sold through Artrock in San Francisco- a large portion of the run (including this example) were HAND-SIGNED by Ken Kesey (in gold pen, in this particular case)

 Medium-thick oak-tag vellum stock silkscreen poster is in near mint to excellent (A-/B+ to B+) condition; aside from a couple of well-camouflaged soft handling dings hiding within the image area, a small thin bend/crease in the upper left corner and a couple of ULTRA-tiny corner-tip bumps, it is a FANTASTIC example of this always-popular 1960's image with a BUNCH of extra Prankster-added colors/embellishments and a nice large Ken Kesey signature.