Kodi

Kodi is a software application platform that facilitates streaming media. It is the core software behind "Android TV" and other types of streaming media set-top boxes.

Instructions for creating a Kodi-based streaming media system using a raspberry pi and OSMC are here.

Instructions for customizing Kodi are here.

Instructions for implementing RetroPie via Retrosmc are here... but this method doesn't work. Don't use it.

Instructions for implementing Kodi on RetroPie are here.

Instructions for backing up your sdcard for cloning to other systems is here.