We're creating a solution which is basically a ubuntu desktop connected to a projector and managed by a iPad, is there something I can install on the ubuntu box so that I could play a video from youtube from the iPad, using the same thing you use to play to a Apple TV, so instead of 'View on Apple TV' it would be 'View on UbuntuBox'
This should do the trick!
shairport, allows you to stream from apple devices to your linux box just as if it was an airport or apple TB. It works great! https://github.com/albertz/shairport
and airplayer for streaming video. https://github.com/PascalW/Airplayer