Yearly photos w/ interests noted. Make up a few pages in photoshop or an editing program of choice, and create a printed 8x10 book. Give to your children when they graduate as a gift...I would use a few head shots and definitely lifestyle candid shots to get the real feel of what they were like at each age.
This takes some technique and time to achieve the amazing results seen here but it can be done. The link/source has the instructions. Win.