It's not exactly what we'd call a easy jailbreak, seeing as how it requires a soldering iron, a NAND format procedure, and a Logitech Revue that's never even been powered on, but it looks like it is possible to root a Google TV box after all. GTVHacker has a thirteen-step walkthrough to cracking the Logitech Revue -- and physically crack the case you must -- after which point custom firmware can let it download, install and run apps from Android Market and bypass pesky television network blockages. Risky? Definitely. Worth it? Depends on howpatient you are.
Update: Looks like the GTVHacker team won themselves $500 for their trouble, due to the hack's likely use -- it may give developers a head start building apps for Google TV's version of Android. Find the details at our more coverage link.