The Merry Prankster's bus and their destination. A symbol of the 60's and psychadelia and Ken Kesey. Read The Electric Kool-aid Acid Test for more information.
Why am I the first person to define this?!
"The painting job, meanwhile, with everybody pitching in in a frenzy of primary colors, yellows, oranges, blues, reds, was sloppy as hell, except for the parts Roy Seburn did, which were nice manic mandalas. Well, it was sloppy, but the one thing you had to say for it; it was freaking lurid. The manifest, the destination sign in front, read: "Furthur," with two u's." --Tom Wolfe