In case you haven't tried it, Sun has an awesome program for any tech guru to play around with. It's called VirtualBox, and it's an open source virtualization package developed to run on a wide array of host operating systems.
What is virtualization? The concept behind virtualization is rather simple: take an operating system and run it within your current operating system. This essentially gives you two computer systems to play around with, although the second (called the Guest) can only utilize resources allocated to it by the main operating system (the Host OS). A guest operating system can enable you to test software on a variety of operating systems, and do all sorts of bug testing without fear of damaging your host computer.
How does it work? The basic principals are easy. Your main operating system allocates file space on your hard drive (just a giant file, which acts like another hard drive to the guest), and it allocates virtual system resources, such as a software-based graphics card to render the guest OS onscreen. In addition, it gives the guest the ability to pass up commands to the host operating system, if specialized hardware calls are needed: for example writing to a floppy disk drive.
What can I do with it? If you don't have a specific need for software testing, there are still a myriad of great reasons to use VirtualBox. You can, for example, test different flavors of Linux/'Nix operating systems, to see which you prefer. You can try an operating system as advanced as Sun's OpenSolaris - and see how it compares with what you're used to. You can enhance your knowledge of computing overall through playing around with all sorts of things on a virtualized guest operating system.