The ScreenInvader is a debian based linux distribution, all about presenting content on a screen and sound system - it is best described as social tv.
It almost exclusively is developed at the Metalab Lounge.
You are looking for the ScreenInvader if you'd like to:
watch videos, music, images, pdfs or web pages stored on your laptop or from the web on a big screen.
share media content with others
create playlists collaboratively
hack while you slack :)
Since it's just a software distribution you'll need to install it on supported hardware.
Please checkout out the getting started guide for instructions on how do that.