The next Critical Mass ride is on for Friday, with riders meeting before 7 p.m. at the Washington Monument in Mount Vernon and heading out on the hour.
There's a map of the route here: https://sites.google.com/site/baltimorecriticalmass/may-2010-ride
The route is about six miles and you don't need a bike. You can bring your skateboard and roller blades. And whistles, noise makers and costumes (that won't make you crash) are encouraged -- as are helmets, water bottles and bike lights and cheery attitudes.
If you've never heard of Critical Mass, these are rides where non-car people take to the streets to exert their right to be there -- and to have fun. No one is supposed to break traffic rules or cause road hazards, though a little disruption for attention's sake is the point.
I've seen more experienced riders do their best to keep an eye on less experienced riders, if you're concerned. They will stop in intersections to make sure everyone gets through okay.
These rides have developed all over the world. See a list here. In Baltimore, riders used to meet the last Friday of every month, but I don't think it's that regular now.
If you know more, let us know. If you go, tell us how it went.
Baltimore Sun file photo/Gene Sweeney Jr.