In case you missed this in the comments section, Ann suggested a terrific alternative to the painting boards I mentioned in my art supplies post:

For painting boards, I bought 3 large plastic food service trays for about a dollar each from our local university surplus store. Each one can hold a large sheet of watercolor paper nicely and the low rim all around catches any dribbles. The quirky part is that they all have the word “Nourishment” written on them with permanent marker. I guess the trays were used by the Univ. Hospital’s dietetics department in their previous life. We just laugh and agree that painting is a *very nourishing* pursuit!

Thanks for the tip, Ann!