I'm trying to solve what must be a pretty common problem but to which google has not yet yielded a satisfactory answer. If a member of the unwashed masses happens to be visiting your abode and asks to use your computer is there a nice, technically elegant solution to the problem that does not entail convulsive shaking of your head and hunching over your machine in an ever more protective pose?

More seriously I was wondering if there's a way to launch a VM (say virtual box) and stop the user from getting out of it. Does VB or any other VM support a password requirement for leaving the VM (i.e. say in full screen mode)? This strikes me as more elegant than setting up a locked down account and having to worry you haven't locked it down well enough (default permissions will let users look into each others home directories I think). Though failing this if anyone has ideas for another way to set up a per-user kiosk thing it would be much appreciated.