Graupner is a popular vendor of RC equipment here in Europe. I thought it would be great if we could use they telemetry protocol for ArduPilot. And here it is, HoTT v4 for use in ArduPilot for everyone. It's still fresh code and it's tested with ArduCopter v2.7 on APM2 only, but it works fine since few weeks. There are many possibilities to use HoTT in ArduPilot project, at least for people with HoTT RC equipment :)
For more details about HoTT and the implementation visit project homepage.
Here a sample screenshot:
Hope you like it!