From the Critical Mass list via SHIFT:

• July 25, 1896 – 6,000 bicycle parade down Market Street, San Francisco, in demand for good roads (be careful what you ask for)
• July 25, 1997 – 6,000 bicycle parade takes over San Francisco (corrupt Mayor, police attack with mass media uproar conveniently masking major transportation scandals)
• July 25, 2003 – Bike Summer NYC * New York is tasting the nectar (Still battling for the right to ride)