Hagrin.com

The Free 60 Project has a Wiki setup that explains the progress of their project as well as offering insights to the inner workings of the Xbox 360. Of note, their documentation offers some insights as to the design of the Xbox 360. Specifically, Free60.org has the following features listed:

• The flash is encrypted with a per-box key
• The key is stored inside the CPU
• The boot ROM is stored inside the CPU
• Also inside the CPU is a hypervisor that verifies the running state of the kernel, making sure there is no modification (RAM checksums), else the Xbox360 panics and blows up!
• The CPU contains RAM inside of it to store the checksums
• All interrupt/exception handling is done by the hypervisor
• All code runs in kernel mode
• The emulator for first generation games can be updated via an official Microsoft download burned to CD by the user, though the CDs' content will be encrypted and signed with public key cryptography.

I'll definitely be following the development of this project since there will be a fair amount of kernel hacking going on. After reading this, the first thought that came to my mind was ... rootkit.