Proxmox, create and administer OpenVZ, Xen, and KVM virtualization with a GUI web interface
I've been playing around with Proxmox for about a month and I really like it. It's a really easy setup if you want to do some virtualization at home for the projects you need it for.
I use OpenVZ containers to test software. It's nice to test a new program or script on a fresh system so that no problems with existing software will interfere.
Basically, what Proxmox does is offer you an easy to install graphical environment that you can use to create and manage virtual machines. It is administered in the web browser and allows you to work with OpenVZ, Xen, or KVM virtual machines.
I'm a complete newbie when it comes to server virtualization, but Proxmox made the process of getting up and running really simple. It's really easy and right now I'm only using it on a computer at home to run several different Linux instances.
Proxmox is easy to install on Debian or you could do as I did and install Proxmox using their bare metal installer ISO which will configure everything for you. I should also mention that I was able to install the Proxmox bare-metal installer ISO on a Virtualbox virtual machine on my main desktop computer.
Running OpenVZ instances doesn't get any easier than with Proxmox.