Props to TSE. There is nothing, nothing, you can do that's more exciting to a teen than to take them for an afternoon of shooting Not video games, not girls, nothing.
For the rest of us, the next time you go shooting, round up your kids and some of their friends. A couple boxes of 22 shells, a box of 12 guage shells, a portable BBQ and hotdogs and pop for a tailgater parter, and you've got a dirt cheap afternoon of entertainment that you'll probably be shocked at how much fun teens have.
My son still remembers fondly a couple years ago when he shot his first pheasant at a similar event, organized by volunteers and businesses. It's a memory he'll have for this lifetime.