Ashlee at Two Naps by Noon came up with a great idea for a long-term project that will be a huge hit with your child when he/she graduates.
Write a letter to your child each year at a specific time, including interesting facts about them from the previous year, and include some cash. Then, however many envelopes you have, you can give them one per day leading up to graduation. I think I'll do mine at the beginning or end of each school year and possibly give to them in the days leading up to the time they move away for college.
They will have lots of "love letters" to send them off and a nice little nest egg to get started.
I just wish I'd known about this when my kids were younger!