Sort of related, the talk about the "good old days" of taking your bike out and exploring, one thing they have down here is something called bike party. Once a month, a few thousand people on bikes get together and get drunk/high/whatever on a route thats usually about 27 miles (40km I think?).
http://www.sjbikeparty.org/
I've done it a few times, its pretty fun. Or what I remember of it anyways. Some people really get into it and have floats and everything for a theme. Other cities should pick it up.