On the last Friday of every month, cyclists around the world gather to ride the streets together to assert the rights of non-automotive traffic to use the streets.
In Calgary, we meet at Eau Claire (near the Olympic arches and the YMCA). The rides usually leave no later than 6pm, and take a generally random route (determined by the riders) through downtown and sometimes into other inner-city communities.
Official Website: http://criticalmass.meetup.com/15/
Added by Grant Neufeld on July 20, 2006