X (the service commonly providing the *nix GUI) was pretty much built with this in mind; Linux has had an implementation of X that has provided this since at least the mid-90s.
Windows has had this on the server since at least Windows Server 2003, and has also introduced it to the "consumer" market in Windows 7.
(I'd be happy to find out whether OS X supports this or not.)
I tried to do this couple years ago for Linux, asked around, and was told this was not possible for Linux.
Apparently I was misinformed. I'm happy to be wrong about it. Can you point me to instructions for doing it for Ubuntu?
I have Windows XP, and have had 2000, NT, 98, 95, etc., and none of them could do it.
I'm glad to see that finally this "40 year old technology" is getting onto desktops in the last year or so.
Do note that there are 2 ways to share a graphical user interface on X.
The first way is by remotely running a program on your own Xserver. The programs' processes occur on the remote connection and are sent down the SSH tunnel and show up on your display. This is the common way in Linux.
The second way is by an older program from the Windows world: VNC. VNC takes a local, running display (example: my gui) and allows someone else to view/control it at the same time I do. In this method, you both fight over the mouse and keyboard inputs.
There are several others as well. There are a couple different ways to make a "multi-head" setup in linux, which is what it sounds like. Multiple monitors/keyboards/mice all attached to the same computer allowing multiple people to run X at once independently.
X (the service commonly providing the *nix GUI) was pretty much built with this in mind; Linux has had an implementation of X that has provided this since at least the mid-90s.
Windows has had this on the server since at least Windows Server 2003, and has also introduced it to the "consumer" market in Windows 7.
(I'd be happy to find out whether OS X supports this or not.)