This is what Taylor and I made Daddy and Grandpa for Father's Day (distant Grandpas, don't worry you'll get one, too!). We made the clay and then simply pressed Taylor's hand in it to get the impression. This clay is really cool! You can store it in an airtight container and keep it as soft clay or make sculptures with it and let it air dry and it will harden. Very inexpensive gift idea. And...Grandpa said the magic words that a handmade gift is the best kind of gift!
I got the recipe from Preschool Art, but there is a very similar recipe here.