A second Led Zeppelin clue was dropped Sunday morning (Sept. 9) when the band's Facebook page posted the word "Four" in the band's familiar script, thus leading to speculation that a countdown was in progress after the previous "Five" posting.

For those doing the math in their heads, if there's a new number each day that would make Wednesday, Sept. 12 the number "one." The day is significant in Led Zeppelin history for the fact that it was the day they announced their reunion show in London five years ago.

Could this mean another performance will be coming from the veteran rockers? Not out of the question, but also probably not likely given that Robert Plant already has two projects already in the works for the coming year.

Might it be that a DVD of the special 2007 event is en route? That's probably a better guess, as a video version of that performance has been rumored for a while. But right now, it's all just speculation. However, Led Zeppelin's fans will no doubt have some fun thinking about all of the possibilities over the next few days.