You've got a mouse in your house, and it's got to go. You've looked at all the mousetraps on the market, and you're sure you can build a better one. So you make a trip to the Patent Office to get advice from a patent officer.
She tells you the Patent Office has already awarded over 4,400 patents for mousetraps since 1838, and your mousetrap has to be substantially different from the other 4,400 to win a patent. The Patent Office, she adds, doesn't care whether an invention is practical or efficient, as long as it works and is unlike any already patented invention. As you prepare to leave, the patent officer whispers two words to you - Rube Goldberg.
The above illustration is a Rube Goldberg mousetrap which I passed up in favour of the more elegant and hygienic solution depicted at the very top, and which is available on ebay at $14.99 for two. I bought two because the onset of cooler weather means that certain little critters will seek out the warmth of our home in days and weeks to come.
Oh, and by the way, Ralph Waldo Emerson never said, "Build a better mousetrap, and the world will beat a path to your door". According to my sources, the current phrasing of the quotation didn't appear until seven years after he had died.