While I was exploring yesterday, I ran into "Critical Mass". It's a monthly bike ride where THOUSANDS of people participate. I've done a little research and found out the bike rides happen all around the world. The rides are for bike enthusiasts. Be sure to click on the link above for more information.
The Chicago ride looked like a bicycle parade. There were people on roller blades and skates too. The shut down the city traffic for at least 10-15 minutes. People were in costumes, saying "Happy Friday," and sporting a variety of bicycles. Enjoy the photos, I enjoyed taking them!