Furthur - the psychedelic bus that pollenated flower power in America during the 1960s - is back on the road to celebrate its 50th anniversary. And you're invited to take part in the festivities.

Furthur was the brainchild of counterculture icon Ken Kesey. When Kesey had to travel from his home in La Honda, California, to New York City to promote his book Sometimes a Great Notion (1964), he turned the trek into an event by bringing his rowdy friends - a.k.a. the Merry Pranksters. After buying and painting the old school bus, the gang hired Beat icon Neal Cassady to drive them across America, preaching radical self-expression and anti-conformity at every pitstop.

When the bus returned to California, Kesey used it to promote "acid tests" - psychedelic concerts that brought Beats like Allen Ginsberg and hippies together to rock out to The Grateful Dead, who became the unofficial house band for these LSD-fuelled happenings. Their antics at home and on the road would later be immortalized in author Tom Wolfe's counterculture classic The Electric Kool-Aid Acid Test (1968).

Furthur at Seattle Hempfest in 2010.Joe Mabel / Flickr

To celebrate the bus' history, Kesey's son Zane set out in 2014 with a new generation of pranksters - as well as a few original members - and traveled 15,000 miles across America, visiting national landmarks, music festivals and other gatherings while celebrating the bus' legacy. Unfortunately, Ken Kesey couldn't be part of the celebration as he died in 2001.

But Furthur will be rolling through the country again this summer - beginning tomorrow - to promote the documentary based on the 50th anniversary tour: Going Furthur (2016).

Check out the trailer below and click here find out if the tour is coming to a town near you.

Banner Image: Furthur photographed at Hempfest in Seattle in 2010. (Joe Mabel / Flickr)