Hello Al and Angela and welcome from VA.
Apologies up front Al for stealing your thunder about your choice in burger.
For those not in the know, In-n-Out is a burger joint, (Maybe the best) but is only located west of the Rockies here in the US. A double double is their signature buger. Rumer has it they have a secret menu that only employees and those of us in the know are aware of. Since you are all my brothers and sisters, I will share:
Animals Style:
Burger of your choice with hand-leafed lettuce, tomato, a mustard cooked beef patty; add pickle, extra spread with grilled onions.
You can find more non-menu selctions here:
http://www.in-n-out.com/menu/not-so-secret-menu.aspx
Enjoy