i recently participated in the scribble project where artists are invited to attack the same scribble sheets (i chose "loosey-goosey") and interpret the shapes and words however they want. it was really fun! the scribble project blog is packed with inspiring entries from all sorts of artists. lisa, the creator of the project, writes the funniest little blurbs when she posts each sheet.
there is also a scribble project book, which would be great for anyone who wants to draw but doesn't know what to draw. the prompts and shapes are perfect for helping you "jot down what's in your brain right now".
here's my "scribble" (click on it to see it a little bigger):
an in-progress shot: