Earlier this month I got to take part in a weekly bike ride in Merida Mexico. Every Wednesday about 1000 people go on a 6 mile bike ride around the City. This ride is different in that riders actually do share the road.
When the cyclists ride by an intersection with waiting cars, all the riders yell "thank you" to the car drivers for waiting. Also, there's a lot of Good Evenings (Buenos Noches) to by-standers and gawkers.
The group posts photos of the blog here. you'll see mostly average young people with no helmets. Lots of people rented bikes at the beginning. I saw kids as young as 8 riding on their own as well as a fare number of working class Mexicans.
Beyond CicloTurixes, there's also an incredibly popular Sunday CicloRuta: