If you are Chinese (Or Asian that have this) then prepare for some moon watching and sit down with families and annoying relatives!
Idea of the festival is that you and your kinsmen get together and basically just celebrate the fact that your family is intact blah blah and because the moon is suppose to be at its roundest and so it symbolize togetherness.... (not sure if that make sense or not).
Anyway be happy and don't forget to call your grandparents and check the expiry date on the moon cake that you buy.