The challenge is not too strict, you can sketch from YouTube videos, Flickr photos, or from the Sktchy app, so that might be a good place to start the week, to build confidence.
I decided to focus on people at Dublin Sketchers last Sunday, as a little practise run, and it wasn't exactly a success. I just couldn't settle, and I felt that my subjects were unsettled too!
But now that I look at them, and with a little auto-contrast from Picasa, some of them don't look so bad. And that's 11 people!