I took a computer class for one of the jobs I had and the instructor gave us an "any" key to attach to our keyboards. It was for when the directions said to press any key to continue! It was a plastic button with Any printed on it.
Netty it has many uses depending on the application you are using at present. One use that should work in all web browsers is if a page is taking too long to load then simply hit the Esc key and the page will stop loading (this is assuming that your Esc key has not absconded over the prison walls). Capt that reminds me of an episode of the Simpsons when Homer is sitting at his computer and it tells him to press any key to continue, to which he exclaimed "Where's the Any key?"