There are some great ideas here. You can also make a Christmas ornament for each girl and put the date on it. When they open it, they can find a place to put it on the tree. You can use Christmas fabrics, or you can do a theme - for example, take the idea of using some old clothes or a think blanket, and use that fabric for the item. You can get patterns for various ornaments at any fabric store. Another idea is to take scraps of fabric and use a large styrofoam ball. Using a flat-head screwdriver, press the edges of a fabric scrap into a ball. Then take a contrasting fabric, press the edge into one "trench" you just made on the previous scrap, and then do the remaining edges over a blank space in the ball. Take a third fabric, start pressing into existing "trenches", and continue. You wind up with a ball that looks like it's been quilted - the sections look sort of puffy, but they are really just fabric pressed along the surface of the ball. Take a ribbon or a piece of rick-rack, and press it deep into one section of the ball with a skewer, and that is the hanger. These are easy, and best to do with thinner fabrics like calicos or cottons. You could use a sharpie marker to put each girl's name and the year on it, or you could purchase a small hanging plaque or charm at the craft store. I love the other posted idea of little purses - you could make them to match the ornaments if you like. You could also make those photo bulletin boards with larger remnants of fabric and some ribbon which you criss-cross and secure with craft pins.