Any family vacations with the kids? do events tendto be clustered together that you are going to have a number of bloxks that have significant life events and then a bunch without? Maybe rather than putting the years in order, you can mix them up so you could scatter the "special" years among the years that things are just going along routine. It could then kind of be like a treasure hunt. Also, I don't know how old your children are, but are there events they remember that you could include on the blocks? Special holiday memories? Funny events that happened that they remember? Sometimes it is the little things that commomorate time together.