Cool Birthday Time Capsule - spray paint an old tin and mod podge a picture from baby's one year shoot and a message. Ask everyone to bring something for it, and have everyone sign the tin as well. I think you could do it every year Hefele Hallows Morton
Time Flies Vintage Airplane timeline for the journey of my parent's 40 years together (a photo a year - yikes! can I find a photo from each year? - would be cute to do with a kids year of first for a birthday party.