Using Xen for System Administration. Neat idea, basically give each user their own virtual machine.
One of my hosts is hosted by the excellent hosting provider Quantact, and this machine is a Xen slice. I just love it, it's fast and responsive, and it has a really cool backup system where I can create an image of the whole machine to restart from.
This is tougher to do when running your own dedicated remote host, like my other server at iWeb, where I have to be more careful when doing my system administration.
This whole virtualization with Xen and things like it is very cool, and we've just seen the start of what we can do with it.