We celebrated for a week last year!! At all the sit-down restaurants, we got a free dessert of some sort. A couple places gave us a card signed by the castmembers working. At PCH Grill they actually brought us out a bouquet of 25 balloons in honor of our 25th Anniversary!!!
Just make sure to mention that you're celebrating....Most places will do something!!
They also have anniversary buttons available to wear (just like the birthday buttons).