When Microsoft calls a last-minute press conference to make a "major" announcement, there's only one sensible thing to do: pack your bags, fly to Los Angeles and get ready to hear what Ballmer & Co. have to say. With no hints whatsoever (not even a cheekily worded invitation!), we've nothing but speculation and rumors to guide us as we head into this news conference. Will we hear about Win8 tablets -- specifically, a Kindle Fire competitor running Windows RT? Or maybe today's news elaborates on Xbox Music? All we know is that it won't have anything to do with Windows Phone, seeing as how Microsoft is holding another press event just two days from now where it's promised to give us a sneak peek at Apollo. Oh-so mysterious of Redmond, and all the more reason for us to host a liveblog. The doors here open at 3:30pm local time, so stay tuned as we bring you up-to-the-minute coverage on Microsoft's big reveal.