Steve Hanov has created just a hillarious app to create an imprecise line-drawing app with the following Features:
- Box, circle, lines, and curve primitive shapes
- Shadows when supported by browser
- Text in several hand-drawn fonts rendered on the server
- Rotate & scale shapes individually or in groups
- Save drawing to a browser bookmark
- Select colours using an HSV colour wheel.
- Unlimited levels of Undo/Redo
Just go and check it here.