I wouldn't touch this with a ten foot pole, personally, but if you're an insufferably curious geek, it seems you can pull down a pirated version of Microsoft's New Xbox Experience. The NXE is Microsoft's impending total makeover for its Xbox 360 dashboard, which I recently previewed here and here. I say "early version" because I can confirm Microsoft's been releasing periodic updates to the NXE, so it's probably not the most recent version.
Furthermore, Microsoft has a very simple means of tracking who's supposed to have access and who isn't. I won't say how, but use your imagination and it'll come to you. If you download the update and connect, they'll also know you're not a card-carrying club member, at which point, says Microsoft, it's bye bye Xbox Live for you.
In case you think that's just grandstanding, Xbox Live director of programming Larry Hryb, aka "Major Nelson," Twittered the following on Saturday:
A little reminder: If you get your hands on NXE and you are NOT in the Preview Program. You won't be allowed on LIVE.
Update: Microsoft's Hryb confirms in a podcast (per Videogaming247.com) that the NXE isn't quite finished. Says Hryb: "...we're still just buttoning up all those loose ends, making sure everything works just right."