In OS X, when an application decides that it needs your attention immediately, it bounces in your dock. Sometimes this is desired behavior, because it certainly draws your attention. But other times, you'll be busy getting work done, gaming or watching a full-screen video, and the non-stop bouncing is an annoying distraction.
I wrote this utility to disable the ability for dock-icons to bounce. Run it once to disable dock-bouncing, run it again to re-enable.