Hi guys,
A few years back I started a company called Playtomic which shut down. I've started open sourcing and continued developing some of the cool stuff we had at Playtomic.org which includes leaderboards, achievements, user created content, dynamic content and geoip with massive platform compatibility, all as a self-hosted platform under the MIT license which is super liberal. There's currently six heavily documented APIs available including extensive test suites for each platform, and then the server component is NodeJS (server-side JavaScript) and really easy to get running.
Links:
- http://playtomic.org has neat examples exploring the api capabilities
- https://github.com/playtomic has all the source code repositories
- http://playtomic.org/server.html has server setup instructions
- http://playtomic.org/apis.html has all the api downloads, documents and source repo links
Enjoy!