My online ATC trading site has a great game set-up called Pay-It-Forward (PIF for short). Basically you claim an offer of a card from the most recent person to post and then offer your own card for the next person to claim. Some of the threads have specific themes, such as one only accepts watercolour painted cards. One that I'm really enjoying taking part in is the Regional Animal PIF, since I love getting to paint Australian animals. Below is my numbat card. The numbat's habitat is a very small area of Western Australia so I've never seen a real one before but it's still my favourite animal.
Card 67/ 365: Numbat