I know that every operating system worth using supports multiple independent users; this makes it easy for several people to share a single computer, with their own documents and everything. However, there is one small problem: the sharing can't occur simultaneously.
Remote Desktop or other similar software allows people to connect to a computer from somewhere else and log-in as any user, without disturbing other users. However I wonder, isn't is possible for multiple people with different user accounts to use a computer at the same time, locally, via multiple monitors and input devices? I tried plugging in a second keyboard, mouse and monitor, however, Windows will mirror or extend the display to the second monitor and the second set of input devices become pretty much like... well... I can't think of anything useless enough to compare them to.
How would I share a single computer with different people? Assume I have a keyboard, mouse and monitor for everyone, connected to multiple video cards (either multiple outputs on a single video card or one monitor/card).