Bicycle Day.

Today is the anniversary of Bicycle Day {wiki}.

At 4:20 in the afternoon, on April 19th, 1943, the Swiss chemist Albert Hofmann deliberately ingested 250 micrograms of LSD-25, a substance he had discovered during experiments with alkaloids of the fungus ergot. Despite the vanishingly small dosage, he soon found himself stricken with dizziness, euphoria, and an inescapable compulsion to laugh. Within the hour, he could barely write or speak intelligibly, and fearing he’d poisoned himself, rode his bicycle to his nearby home, called a doctor, asked for a glass of milk and collapsed on a sofa.

Read about what happened next at Page 3.14. Link -via Grow-A-Brain, who has more links on the subject.