The folks at fireCore have released Seas0nPass, a jailbreak application for the second generation Apple TV. Seas0nPass is a tethered jailbreak solution that requires you to connect your Apple TV to your computer briefly during boot. Similar to the Pwnage tool app, the jailbreak application lets you load custom IPSW files onto your Apple TV.
While Seas0nPass is new, fireCore is a name that should be familiar to Apple TV owners. This group also released aTV Flash, a software package that adds streaming services like Last.fm, an HTML 5 web browser and more to the Apple TV. The latest version aTV Flash (black)