No one else saw what Tex saw. Tex described it as:
It was a totally different index...with a different look aesthetically..it has since disappeared.
Danny posted a screen shot of the green home page, which has since been pulled:
Danny explains this is part of Microsofts Searchification event to be held later this month.
Microsoft has invited a number of bloggers and journalists for the event next week, on September 26. But Microsoft apparently can't wait to release some things, since Live.com is now sporting a new home page.
So if you saw it, it was real and don't think you are going crazy.
Forum discussion at WebmasterWorld.