While out shopping the other day we stumbled upon these fun Crayola Window Crayons. They have a lid and twist up from the bottom when they get dull. The crayons are a bit bolder than the white board markers. They wash right off the window but they don't wash out of clothes as nicely- be warned.
One door, two sides- a new art easel and it's not taking up any extra space in our house. A nice way to spend an afternoon.
I think we might take these on our next road trip, with maybe a small white board. We can doodle on the car windows, play games, keep score... all around multi-purpose entertainment.