Glasses for a player that can be adressed with a unique ID and show an overlay to the player which can be customized by a computer (like the terminal glasses in OpenPeripherals).
Using some kind of connection block that the glasses have been linked to and a computer next to it.
Also, it would be awesome to be able to put on the glasses in a specific "glasses" slot in the curios inventory, if curios is installed

They've been implemented by #59 and are in 0.5b, so I guess this issue can be closed :D