In my day job at Green Hippo I've been working on various automation tracking projects recently, implementing a variety of proprietary automation UDP protocols. However one of these was PosiStageNet, a open protocol for positional data streaming maintained by VYV.
The protocol allows transport of position, speed, orientation and status/naming information for multiple defined 'trackers' using a nicely-extensible chunk format. After some discussion with VYV I requested an addition to the specification for some extra tracker information, adding acceleration and target position (this is version 2.01 of the protocol), allowing for more accurate positional estimation on the client side.
On the official site you can download a C++ implementation, and I originally developed a C# wrapper around this. However wrappers often feel like an ugly solution to me, so I decided to replace this with a full C# implementation. In the name of standardization it seemed sensible to make it both a portable library (creating some interesting opportunities for mobile usage) and open-source. After a few scattered days work over the last month or so, I've just released the first version of Imp.PosiStageDotNet via NuGet.org.
My hope is that with this library (and the original C++ implementation) the entertainment control industry can start to unify around a single, well-defined and appropriate protocol rather than the back-of-the-envelope ASCII formats which many have been using to date. Of course, as with all standardization attempts this may be futile, but at least I have something to recommend when asked to specify a protocol!