Freed from jail, Cassady began to travel again. During the 1960s, he joined Ken Kesey's Merry Pranksters, who traveled back and forth across the United States in a bus, holding "acid tests", a name for LSD parties. Cassady drove the bus. He acted as merrily as anyone, and as full of energy as a young man, when the Pranksters were around. In private, though, he was not enjoying his life, and old friends noticed he looked very tired.