Antoinette Portis wrote a book titled, "Not a Box." This book is super cute and captures the mindset of children before we put parameters on their imagination. This is a great book to read with kids! Children can make predictions on what the box might be (maybe they'll come up with something not mentioned in the book), and they can start to recognize patterns/words (because every other page the bunny says, "It's not a box"). This is also a book that once you read it with your child a few times you may see them pick the book up and read it to themselves. This book is also a great reminder to adolescents and adults to think out and inside of the box (pun intended).
A superfantasic, totally cool, 'wish I had one of those when I was little' is the bilibo. This object is shaped like half of a turtle shell. Parents would always ask me, "Why would anyone want that?" Are you crazy! Who wouldn't want one. These things are awesome. It allows you to use your imagination to do anything you want with it. You could pretend to be a turtle, an alien, an adventurer, a bug. You could use it in the pool, down a snowy slope, in the sand box, with the snow, to dig, to throw, to build, the possibilities are limited only by your imagination. Haven't you ever seen kids playing with the box. They usually passover what's inside and have more fun with the box.
If you've never heard of either of these things check them out!