The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
From Brilliant AiRiC:
Tired of using your legs and arms to jump rope? Now all you need is one finger! "Jump Off" is jump rope for you finger. Hold your finger down to begin. Earn points when your finger is down. Jump over the rope but make sure not to drag your finger! There are 4 different difficulties Beginner, Intermediate, Challenging, and Expert. The rope speeds up and becomes unpredictable. The screen shrinks and makes it harder to see the rope. Collect smileys that slow the rope down, earn you points, widen the screen, and even reverse the rope. Online and local leader board included thanks to Openfeint. Made with Cocos2d.