The details about the daylong sunrise-to-sunset cache machine are in this forum discussion, but the official event is the after-machine dinner.
Dinner will be at the above coordinates: China Buffet, 2600 Yakima Valley Highway, Sunnyside. Be there at 7:00 p.m. on Saturday, September 22, 2012.
Be sure to put this on your watch list now, so you'll be the first to know about changes and updates as the big day approaches! A "will attend" note here will be greatly appreciated in order to help plan dinner arrangements.