On our wall we have a white board. It's been there since we moved in and it existed on our wall in the loft, too. It lists important dates, our to-do list, shopping lists, etc. This weekend, I added a second piece of scrap (which had been in the loft as well, and stored in the current house.) I picked up a bucket from the $1 aisle at Target and a $5 package of dry-erase crayons. New favorite toy.
And yes, he does erase with one hand and draw with the other. It's adorable.