Misti Ko from Burnaby, British Columbia has a cool thing going. It's an ATC jam, an artist trading card where 3 people contribute to one card. She starts the original one with a rubber stamped image of a pencil and mails it off to a friend. Friend adds to the card (in this case, the red dotted background) and then mails it onto a third person (me). I added the silly line drawings of kitties.
Here's another example. The third person on the jam card mails it back to Misti where she uploads the finished ATC to her blog it-starts-with-a-pencil.blogspot.com If you want to participate, e-mail her to get started.
The upcoming winter issue of ATC Quarterly will feature a spread of Misti's adventures in jamming. Be sure to check it out!