The Billy Goat Tavern is a Chicago establishment. Way back in the day when SNL first started, there's a skit about this place. "Cheezborger, cheezborger, no fries, chips" and there's actually a guy who says it just like that.
The Double Cheezborger. They seemed fairly unasuming until I tried one. Flavorful and delicious thin patties of meat served on one of the best buns I've had. They hand you the burger in paper and you add the condiments of your choosing at a little counter. I've been in twice and it's always busy.