A wee while back I bought a $3 pack of markers from the warehouse. I wrote the boys a note "Mummy and daddy are sleeping in till seven o'clock. Please don't wake us up. There are new marker pens for drawing and paper..."
I also left out some handmade books (just cut paper stapled into a cardboard cover) and the boys made an animal book each. They were gorgeous and the sleep in divine. I think I need to do it again soon.