I've been playing with Kodi (once known as XBMC) which is a slick open-source media centre system that runs on almost everything (OSX, Linux, Raspberry Pi, Android, Windowz, even [jailbroken] iOS). I wanted to connect it to MythTV, which is rather a handy open-source DVR for TV streaming and recording. So in Kodi (v15.1) I went to System->Settings->Add-ons->My Add-ons->PVR Client->MythTV PVR Client and then added the IP address of my MythTV server. That's all then I thought... so how does it work...?
It's not entirely obvious - but very simple when you know how - you then need to go to System->Settings->TV->Enable and just enable it! Then a new TV menu item appears on the main screen with various options for interacting with MythTV - like watching live TV, or recorded shows etc.
Also it seems that one can reduce the CPU load when running Kodi with the current versions by switching off the RSS display on the main screen by going to System->Appearance->Show RSS news feeds and disabling the option.