With my nephew turning 7 later this year, I'm going to introduce him to model rocketry. My brother and I both grew up launching (and losing!) many rockets over our years, so we're both familiar with the concepts and systems.
But with the purchase of my 3d printer, I've seen the possibilities are endless.
I designed, and built a collapsible launch pad, that not only looks cool, is very stable, and a later iteration of it will make it modular so you can add multiple launch rods to the same pad!
http://www.thingiverse.com/thing:588121
Just found a cool rocket I'm going to be making too!
http://www.thingiverse.com/thing:761156/#comments
And then to top it off, I found an open source rocket designer and simulator. This should be a lot of fun!
http://openrocket.sourceforge.net/
And using an arduino based system, I'm building a custom launch controller. It will have a key locked power switch, a big safety covered arming switch, LED lit of course!. It will also have a digital countdown display, and pad selection. I love being a a kid again!
The other day I was at the hobby shop, getting parts for my boat, and I found an Estes rocket catalog. I remember drooling over that as a kid, it was my porn as a young kid. Turns out it still is!
(Ok that sounds bad, don't read too much into that!)