Progressive thinkers sometimes feel like aliens in this city of aliens. Critical Mass, a bicycling staple elsewhere, is growing here as the city fills with educated idealists. Activist groups Emerge Miami and the Miami Green Party have teamed up with the Wallflower Gallery and Sweat Records to make trips to Matheson Hammock, the Everglades, Miami Beach, and Calle Ocho. So get on your bike and start a conversation about civic responsibility with the girl in the ripped shorts and wire-rim glasses. Just don't forget to ask for her number when the ride ends.