You can't do much besides noodle around with the command line (yet), but Pwnage Tool 4.1 lets you jailbreak the new Apple TV, as well as your other iOS devices. Knowing how quickly the jailbreak community works, you'll probably be able to customize the UI by the end of the week and watch season 2 of Freaks and Geeks from some alternate dimension by early November. [Dev-Team Blog]