I have gotten a request to roll out a total of 8 internet cafe's in a large network. Budget is non-existent as it will all be done for a non-profit. I was planing to use Ubuntu and live-cds to minimize the amount of management required, but I can't seem to find any suitable internet cafe system that is Ubuntu based. The requirements are pretty basic: It needs to keep track of logged in time and log out users when their time it up. No billing will be done, it will just be used to ensure people can share the computers fairly. It should be possible to force logout from a central system. Users will be unskilled, so it has to have a GUI.
What (preferably free, considering the shoe-string budget) software would you suggest to manage this?