I know it is short notice but this idea is very easy and doesn't require a lot of materials. I made this a few years ago for my husband and he loved it. You take a plain T-shirt any color and different colors of fabric paint. Put the paint on the bottom of the kids' feet and let them put 2 footprints on it. Then you put the letters "My kids walk all over me" on it with the paint and voila a nice, sentimental Father's Day gift.