Three inventions -- free, for you
1) A foldable tennis racket --- a good idea when traveling
2) An inflatable suitcase --- to let cab-drivers think you are going to the airport when you are just going a few blocks away and it's raining. (Not advised with surly cab-drivers.)
3) Paste-on pointed thumbs --- for use on Blackberberries. Why hasn't anyone thought of that? Must I, an authenic technophobe --- think of everything?