You don't really go to Organ Stop for the pizza. The organ is fun (especially for Grandma and Grandpa - as well as kids).
Ordering is a bit of an adventure - cattle call ordering line where they give you a number and you come back in another line to pick up your food. There is also a third line because you can not order your drinks (soda, beer and wine) in the line where you order your pizza.
The pizza is made on a chain belt and is average at best. I was pleasantly surprised by the lasagna I ordered and the spaghetti looked good but I didn't try it.
The real star of Organ Stop is the organ and the man who plays it. It may sound corny but it is fun and it is a hoot to see the older gentlemen stand up and salute when they play "Anchors Away", "Nothing can beat the US Air Corp or "The Halls of Montazuma"
In Summary - average pizza, above average entertainment - worth taking your parents or grandparents to when they visit the Valley!