I came across a recipe for sidewalk paint recently (and can't remember where or I would link up!) so we painted on the sidewalk yesterday.
The recipe is super simple: mix 1 cup water and 1 cup cornstarch. Separate into a muffin tin or cups and add a few drops of food coloring. That's it! It looks kind of dull going on, but when it dries it brightens right up! It washed off the muffin tin and paint brushes well. It's supposed to rain today, so we'll see if it washes off the sidewalk as well. Lots of fun!