My son is two and just loves his chalkboard and dry erase boards. We bought him one in a zippered bag that's nice for taking in the van.

Something else we do is buy rolls of paper (at Wal-Mart for about $1.75). I cut off large pieces and tape them to the coffee table. The whole family contributes to the art work over a few days. We practice our letters and numbers. It's a lot of fun and keeps the coffee table from getting marked up too.