I got this from [Kellan](http://laughingmeme.org/articles/2006/09/05/world-metros):

Here’s a list of the various public transportation systems I’ve ridden on:

Make your own at: b3co.com!

Sadly, they don’t have a selection for the Portland, Oregon [TriMet](http://www.trimet.org/) system… but I’ve been on that one, too!