It's not commonly known, but the first "Acid Trip" was on a bicycle. Albert Hofmann, the discoverer of LSD took it in 1943 when some of the substance accidently got on his finger and he pedaled home from work.
http://www.hofmann.org/
At 102, he was certainly a 50+ cyclist. He had a lot of affect on my life, and I'm sure affected many others.