I set it up a few years back in highschool. They had all of these pitiful boxes with 128-256mb ram that couldn't handle XP. One day I was rummaging through stuff that got donated and I found a motherboard with dual Opterons (unsure of the specs). Ended up setting it up on a cardboard box in our 'rack' which consisted of a empty janitors closet where we kept the router.
The XP systems had all of the stuff stripped off and were setup to remote to the Opteron box, which was running Windows 7, where the user would then log into their account, etc. Cheaper than buying 40 copies of Windows 7 and new computers to go with it, and so few use the computers at the same time that it doesn't bog, even with 8ish gigs of ram.
That computer had an ethernet port on it die, the user couldn't log in so we put a spare ethernet card in it. I'm sure if I walked around the school I could find that many hours on most of them, they don't turn them off.