Every year in San Fransico on Easter for the past 7 or so years there has been an event called the BYOBW (Bring Your Own Big Wheel) Race, and this year is no different! The event is at 4pm on April 12- conveniently the day before the Yosemite adventure begins... Just sayin'...
Here's some links to pictures and videos:
BYOBW: Bring Your Own Big Wheel Race
Photos and Videos from previous years
More 2008 Photos and Videos