What is the secret?

I think it is great your children want to be involved, I would like to know what the secret to that is??? I have a wife, 23 year old girl, 20 year old boy, 13 year old boy and a 10 year old girl none of which are interested in my coins or paper money. I take that back, they would like to know if they can spend it. I have started collections for all the kids as each one has a complete circulated set of Lincoln cents, statehood quarters and now presidents. The two that are still at home have 20th anniversary silver sets and various other coins and bills but it does not interest them in the at all. My wife sometimes looks at me like she is waiting for my set to reach a certain value so she can knock me off. The only one interested is my 2 1/2 year old grand-daughter who loves all of it and can sit and look at it for hours. She has her own coin tubes full of pocket change she can play with all day. So that leaves me with my original question, what is the secret?