1120 SW Fifth Ave, Suite 800, Portland, OR 97204
TriMet's How We Roll blog has a nice slide show of the art on its monthly passes.
Click on the image to view the entire slide show.
Speaking of historic TriMet tickets: if you have old, pre-foil TriMet tickets, they are no longer accepted on buses and trains. You can exchange them for new tickets at TriMet's customer service center at Pioneer Courthouse Square.