A long, long time ago (well, it feels that way - but really it was just last year) I took part in the Sketchbook Project coordinated by Art-house Co-op. You sign up to take part, pick a theme (I picked Jackets, Blankets and Sheets), they send you a sketchbook and you have to fill it. Simple. I'd completely forgotten I'd done it, so it was nice surprise to get an e-mail telling me that my sketchbook has been digitized and is now online. You can see it here! And maybe sign up to take part in the next one while you're at it.