atcsforall.com. This one is called the "Summer Solstice a-thon".
An art-a-thon is an online gathering where artists make art (any type - drawing, painting, collage, etc..) around the clock and around the world - ATCs (artist trading cards), inchies, chunky book pages, and anything else they have a whim to make. Lots of fun and inspiration.
Most artists opt to trade their art with each other, and it often becomes a whirlwind.
I'm already caught up in the frenzied trading this weekend:
My closest trade so far: Tennessee
My farthest trade so far: Indonesia
After the weekend is over ... there is the happy anticipation of receiving art in the mail. fun, fun fun!