Vinegar works as a wood stain when you add a metal object in the mix and let it sit in a glass container for a week. A handful of pennies will produce a beautiful pale Caribbean blue stain. A wad of steel wool will give you a rich reddish hue. A combination of tea and a metal object in vinegar will produce a black stain.
Here's a really cute idea. Frame quote bubbles, use a dry erase marker to write funny things your kids say. When you are ready to switch the quotes, have the child take a picture with their quote and make a photo book of quotes. My mom says you think you'll remember all the funny stuff they say, but you don't.