Last fall Microsoft announced that its .NET framework and run time engine was being released as an open source project on github. Many who have followed Microsoft over the years listened to this with a healthy dose of skepticism. Microsoft over the years has not really embraced the open source movement. But almost a year into this journey I am convinced that Microsoft is fully on board with the open sourcing of .NET.
The open source version of .NET is called .NET Core. .NET Core source code is available on github here .NET Core source code. Also, .NET is backed by an industry standard ECMA standard to allow for others to also implement their own version of .NET. Two notable examples of this are Mono and Unity. They have taken the ECMA standard and built their own version of .NET. Mono has been built on Linux, Android, and IOS.
To further this open source move Microsoft has released a version of .NET Core for windows, linux, and OSX. These 3 along with Mono on Android and IOS, allow developers for the first time to develop applications that can run on all of the major platforms. Just recently, Microsoft also announced the purchase of Xamarin and the Mono engine and have built support for this and cross platform development into Visual Studio.
This development, along with the announcement that Visual Studio 2015 is now free, allows developers to use a full featured IDE and develop for multiple platforms all in the .NET world. As this becomes more widely known, I believe, you will see a lot of interest shift back to C# and VB. These .NET centric languages have gotten a little passe with the growth of the mobile market. Up to now there was no real avenue to mobile development in the .NET world except for the small windows phone platform.
This also does not get into the whole benefits of Windows 10 and the develop once for tablet, pc, phone, xbox, IOT vision.
It is a good time to be a C#/.NET developer.