Artist Trading Cards (ATCs), explained in great detail on Cedarseed.com (seriously, read it), can be a great way for you to make art on a regular basis.
ATCs are 2.5 by 3.5-inch cards you make and exchange (no selling!) with others for fun. Not only do you get motivated and make connections with other artists, the small size means you’ve got a completed piece of art in almost no time. Instant gratification!
This is something a group of friends can do. Depending on how comfortable you are with sharing your address, you could exchange cards with people you meet online – or you could just scan your cards and email or post pictures of them.
I did it once, a few years ago, and had a great time. A friend of mine was the contact person – everyone in the group sent her the cards, she put one from each person into envelopes, and then sent them out. I used watercolor with colored pencil on top. I cut them to 2.5 x 3.5 inches myself, but recently I saw some packs of watercolor and bristol paper in that same size – apparently art suppliers are catching on.