Official London 2012 Join In app - plan, enjoy and share your Games experience.Get a pocket guide to the Games! In the summer of 2012 London and the UK will come alive with events, celebrations and activities during the Olympic and Paralympic Games. ADVISORY: downloading the appThe Join In app is rich in data. The initial download is 8MB, but the app requires approximately 60-80MB once fully installed. Some data will download on demand, such as overlay maps, for which a data connection.