The oldest two kids, almost three and almost two at the time, contributed their hand prints in any random place they decided to put them. I only helped by making sure they used an opened hand.
I used a hard backed canvas and acrylic, washable, paint in a variety of colors. We used one to two colors at a time, wiping off hands before the next color application so it didn't turn into a huge brown gooey mess. At the very end each child put on a single red handprint and baby Cordelia added her tiny foot print. I had it professionally framed without glass (which was recommended by the framing person).
I see this every day and sometimes take a moment to remember that day. It was fun. I remember holding a tiny Cordi in my arms and that she really didn't like her foot squishing in the paint. I remember the kids going ape over being able to come in full body contact with paint. I like the unique gift we made for Rob and I think he appreciates it too. Sometimes we compare their hand prints to how big they are now and it always pulls tears from my eyes.
Just another idea for any of you looking for easy, inexpensive gift ideas that also contain a wealth of memories and emotions.