I have been seeing what's called a "card-in-a-box" all over Pinterest, and had to try it for my self. essentially, it is a box card, that easily folds flat for mailing, and it is AWESOME in my humble opinion. It would be great for kids and adults alike, but the one I made up, is for boys.
I used an old "Creative License" Simply Scrappin' kit, since it comes with a ton of perfectly coordinated stickers for embellishing. The only stamp I used was for the happy birthday sentiment. I used the tutorial on Splitcoastand it was pretty good. I though, am going to make another because I found it a little hard to follow, and thought of some tips that should really be incorporated, as well, for a better end product. Have fun and happy stamping!!