Wikipedia recounts "The celebration of Bicycle Day originated in De Kalb, Illinois, in 1985, when Thomas B. Roberts, then a Professor at Northern Illinois University, invented the name "Bicycle Day" when he founded the first Bicycle Day celebration at his home. Several years later, he sent an announcement made by one of his students to friends and Internet lists, thus propagating the idea and the celebration."
As you can see, both these versions of the original Bicycle Day artwork were used to decorate 25 hits of blotter paper LSD.
The problem I have with this image is it conveys none of the fear or paranoia Hofman experienced that day, and chooses instead to picture only the idealistic qualities of LSD.
Over the years many artists have taken a stab at updating the original, & this one does convey just a hint of the menace Hofman felt that day. But my favourite is still the LSD monster (see yesterday's Catboxx), for the way he told it, Hofman's bike ride home was truly terrifying, with the ideal part of the trip coming later that day.