I'll give you a short version, because my login timed out and I lost all that I had written before
.
Two possibilities:
1) XDMCP and/or SSH with X forwarding
2) Ruby/Backstreet ruby
First one is reliable, but slower than the second one. Requires fast ethernet cards: 100Mbit is fine. Google with "xdmcp" for more info. A slower computer is used as a "window" to the faster one via network. In basic use there is only slight difference between the slower and the faster computer.
Second one is tricky, but gives excellent results if made to work. Pairs of monitors, display adapter, keyboards and mice are used to create real multi-user workstation. Allows fast 3D graphics and video playback on both displays. See these links to get started:
http://www.ltn.lv/~aivils/
http://www.ibiblio.org/pub/Linux/doc...ser-HOWTO.html