One of the worst things about growing up is that having fun starts to cost more and more money. First, there's the transfer of expenses from parent to child, which makes that trip to the movies or the go-kart track a little less fun. And then there's the assumption of insurance payments on the hand-me-down sedan, student loan bills, and eventually, new car payments. It gets to the point that everything has that weighty cha-ching sound of hard-earned currency associated with it. And, unfortunately, that vivid imagination that carried us through as kids just doesn't seem to be firing on all cylinders anymore. Our minds are too busy as it is. We need tangible fun. Don't despair. There are people out there who get paid to make fun affordable – like the designers of the Nissan AZEAL concept vehicle.