Fellow writer Susan Chase-Foster told me about Brenda Swanson's Challenge.  I have wanted to do something like this and almost did the Sketchbook Project but felt the price did not match what we all got out of it (small silly sketchbook for starters.)  I started my blog post to follow my sketches; every week I will post them.

http://zenkatwrites.com/2013/06/29/75-day-drawing-challenge/