We're an open source, home media server built from the ground up with all new technology and the .net 4.5 framework. We utilize several other prominent open source products such as Service Stack, jQuery and jQuery Mobile.
In addition to the server, we have nearly ten clients released or in production:

Android
HTML5
iOS
Roku
Windows Media Center
Windows 7/8 (Htpc app)
Windows Phone
Windows RT
Media Portal

Why not join our team? We are looking for new developers to help us on a number of projects.
Specifically what we're hoping to find are:

A developer to assist with the Mono port to help bring MB server to Linux and Mac
A .NET developer to add live-tv support
Any developer who wishes to use our api for any purpose
Strong .NET developers are always welcome (core, plugin, or theme development)

Github: https://github.com/MediaBrowser/MediaBrowser
Community: Media Browser Community Tracker
Promo site: Media Browser 3

Thank you very much in advance