With the advent of technology, family history has branched in many different directions! Since our kids were born digital, give them the opportunity to help you out! This link will give you ideas for your teens to work on family history this summer. Who knows? They may even become family history addicts! Wouldn't that be awesome?
P.S. If the above list wasn't enough, try here. Scroll down to the LDS Young Men and LDS Young Women Activities! Also, google family history activities and you will be well rewarded!