Address Book Server allows you to share your contacts and calendar events with others connected to your network or over the Internet. Each participant synchronizes their contacts with the server hosted on your own system. Address Book Server supports the full Address Book and iCal schema. The server also provides a friendly Web interface and an iPhone client which let you access your contact details remotely.
Playtomic is a set of client and server APIs for game leaderboards, user generated content, and dynamic updates. It began as a hosted service providing tools and analytics for game developers, but is now available for developers to operate on their own. It includes the API server which is written in NodeJS and backed with MongoDB, along with game client APIs for HTML5, Flash, iOS, Android, Windows, and Unity3d games.