Kinect for Windows (K4W) and the Kinect v2 sensor are amazing for NUI development and I'm glad that we at IdentityMine have advanced projects where we can leverage this technology.
The K4W SDK already provides lots of nice APIs and a ton of samples to get started. Like usual, there's always more and an SDK can not cover everything but if the official APIs are well built, the open source community is always happy to provide functionality beyond the standard SDK.
One very good open source K4W project is KinectEx which provides some really cool features one often needs when working with K4W v2. KinectEx brings Kinect data recording and playback APIs, so it can be integrated in your own apps, multiple skeleton data smoothing algorithms and much more.
I've contributed a few changes to the project and the KinectEx author is really open for pull requests. Funnily does KinectEx also use one of my open source projects WriteableBitmapEx.
I just wanted to share this very nice open source project and spread the word.
You should definitely look into KinectEx if you are doing any K4W v2 development.