I thought about surreptitious' discussion on flying, Would You Want To Have Wings? & thought about different things someone might want to develop. As long as it doesn't involve magic, feel free to mention whatever you think of. It can be grandiose or ridiculously simple, as long as you want to invent it. I am assuming you would want to fulfill a need somewhere, so it has to have an application, either to yourself or others, no "useless" gadgets for this discussion, please! So, what gadget would you invent & why?