Don't let the dumb TV commercials make you lose your appetite for Sonic. It's a fun place to eat and has good food.
Get a Coney Dog--they are huge and even come in their own trays because they are so big and have so many toppings. The chili cheese fries are also terrific--the regular fries are just so-so.
Sonic also always has interesting dessert treats -- like apple slushies!