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 Rokk Media Ltd.:
Justin Miles, founded Just For The Challenge in 2011. There are three main aims for Just for the Challenge:* To raise money for charities and raise awareness of the work that they do* To help people to achieve their fitness goals* To encourage people to embark on their own adventuresThe Just For The Challenge iPhone App lets you keep up to date with Justin's challenges and successes and share them with friends on Twitter, Facebook or by email.The app includes Justin's News and blog posts, Twitter and Facebook streams, videos and photos - plus much more.