From people understanding its appeal in comparison to alternative (and aging) tools, to the continued en-masse migration of OSS projects over there (Tracks, mootools, Apple's brand spanking new sponsored sproutcore, etc), to the sheer joy of being able to easily contribute to your favorite projects, to even more people realizing its importance, GitHub has reinvigorated the OSS development world like nothing else in the past almost ten years, I think you'd have to go back to the original SourceForge launch to find something of equal importance. So if you haven't started at least learning how to use git and Github you owe yourself a few hours to do so, even if you're using Windows. Go on! Go on, go on, go on, go on, go on!