Great idea for kids!!!! Buy a white plate ($1 store) and let the kids make a picture with sharpie pens, then bake @350 for 30 minutes.
Also on these boards
These are the most amazing pens I've encountered. I like to draw in pen, namely because it looks sharper, and erasable pens usually suck. BUT these erase with friction (both in gel and marker pen style), leaving NO trace, and no eraser shavings. It erases better than pencils and doesn't smudge during use. I'm smitten.