It will be running from September 11th through to the 19th. From the anniversary of the World Trade Center attack, through to annual "Talk like a Pirate" day.
Or if you're Jewish, this post on 1km1kt shows the coincidences from that perspective.
I like Game Chef because it always ends up challenging my ideas about what a roleplaying game can be, especially when I start looking at what the other contestants have produced.
It gets me feeling experimental, sometimes producing absolute train wrecks, but on other occasions producing something that acts as the kernel for a new track of design thought.
I recommend any game designer give it a try at least once in their design lives.
I don't know what it will have in store for us this year, but it's going to take all of my mental restraint to prevent myself from rewriting my entry and editing it into pirate prose on the final day.
At least I can share the day after the contest with my wife on our anniversary, I'll have gotten a whole heap design angst out of my system for another year (or at least until the next contest comes around).