+Dan Salas The raspberry pi does not use android as the default os, it doesn't really have a default, just a list of recommended  raspbain, archlinuxarm, one of the openelec based images...

I tried running kde on archlinuxarm on the pi once (512mb model) once, sadly it was not powerful enough to run plasma-desktop :(

+Dan Salas you can install Ubuntu on Android, (eg. https://play.google.com/store/apps/details?id=com.zpwebsites.linuxonandroid ), it would be nice to install Active's interface there ;-)