See link below for more information.... I plan on being there!
There's also another one in Chinatown on Saturday. I haven't been to either... anyone been? How's the chow? I'm more interested in going to Arcadia since if the food sucks we can go to Din Tai Fung.
My girlfriend (who is Taiwanese) doesn't know quite what to expect either, since the moon festival in her part of the world is celebrated by eating moon cakes and nighttime barbecuing (since it ends at 5:00pm, there won't be much o' that happening).