Ubuntu on Windows

If you think the ability to run Linux binaries unmodified on Windows, for Windows to provide Linux API compatibility, is "the same as has been trotted before" and "only a niche", you're not living in the real world.

This is a colossal improvement over Cygwin and everything else that's been available for Windows. It's even an improvement over OS X, I don't have to do gymnastics to replace all the ancient BSD utilities that Apple ships with OS X with their GNU counterparts.

And those of us who teach/train people in Python/Ruby/Go don't have to fret anymore when someone shows up with a Windows laptop.