After Apple moved to Intel-based CPUs in their computers, hackers were able to get OS X running on PCs.
It requires a good deal of knowledge, but can give you an OS X machine running on non-Apple hardware.
The guide is very in-depth and we don't recommend attempting this, but it's good to know that nerds that would previously be running Linux are now running OS X because they can.
Be sure to check back for our detailed thoughts on Leopard later this week.
Yahoo News: Apple's Leopard Hacked To Run On A PC