ATC's anyone?

I'm talking about Artists Trading Cards. How come I have been missing out on them before? ATC are a brilliant idea based on the older sports-themed trading cards, collectables. The only 'rule' to these cards are that they have to be 2.5" x 3.5" in size, but other than that, you can go crazy altering, collaging, painting, drawing, or otherwise personify your art.
On the back the name and contact info of the artist, as well as the title of the piece and number if it's part of an edition.

I see them also being sold on Ebay. Not sure what to think about that. How i understand it, ATC's are there to be traded between artists.

Who makes ATC's already? Anyone up for a personal swap of some kind? Random cards or go by a specific theme? Watch out with those exacto knives! They're SHARP!