This community maintained list showcases .NET open source consumer projects. It is intended to include projects that are useful for consumers, such as desktop applications, websites, mobile apps, etc. For developer projects, see the .NET open source developer projects list. PR a change into either list and it will be accepted (modulo duplicates).
Please sort projects alphabetically and provide a one-line description. GitHub/CodePlex (or other source) links are preferred, but feel free to also include marketing sites. Create new sections, as appropriate.
- Media Browser - www.mediabrowser.tv - A client/server application that allows you to easily manage your own media content and present it in an eye catching way. Server runs on Windows, Linux and Mac. Clients are for WP, Android, iOS, Media Centre, Windows, Roku, etc.
- Pinta - A simple drawing/editing program modeled after Paint.NET
- Banshee - A cross-platform multimedia player
- Espera - A media player that plays your music, YouTube videos, SoundCloud songs, has a special "party mode" and an Android remote control.
- Simple Music Player SimpleMP or Simple Music Player - A simple and easy to use music player for free. It plays the most common music files (mp3, ogg, wma, wav) in a simple way.
- Waf Music Manager – A simple and fast application that makes it fun to manage the local music collection.
- Smuxi IM - Free, distributed, and user-friendly IRC / Twitter / XMPP / Campfire / JabbR client for Linux, Windows and Mac OS X
- Gmail Notifier Plus - An app to monitor multiple Gmail accounts from a single, compact point, sitting in Windows 7/8/8.1 taskbar.
- YouCast - YouCast allows you to subscribe to video feeds on YouTube as podcasts in any standard podcatcher like iTunes, BeyondPod on Adroid or even Zune PC and so forth.
- Ember - A simple & Beautiful Screenshot App
- Waf Stopwatch - An advanced stopwatch with a lap recording feature. Additionally, it provides a Countdown with alert sound.
- Waf File Hash Generator - A simple tool to generate the hash values of one or more files. It supports: SHA512, SHA256, SHA1 and MD5 in hexadecimal or Base64 format.
- Zero Install - 0install.de - A decentralized cross-platform software-installation system. Run apps with a single click or control every detail.
- OpenPetra - www.openpetra.org - An administration software for charities that can be used to manage personnel, supporters, book keeping, gift receipting, accounts payable, conferences etc.
- CoiniumServ - A high performance, extremely efficient, platform-agnostic, easy to setup bitcoin & alt-coin pool server implementation. It features stratum services, reward, payment, share processors, vardiff & ban managers, user-friendly embedded web-server & front-end and a full-stack API.
- OpenJudgeSystem - An open source system for online algorithm competitions. The algorithm competitions (currently available in C#, C++, JavaScript, Java and PHP programming languages) are timed contests where all contestants compete online and are given the same algorithmic problems to solve under the same time and memory constraints.
This list is just a starting point - also take a look at all the projects on CodePlex and on GitHub Trending C#.
Thanks to @scottisafool for providing the initial list.