We went to New Haven and visited the place where the hamburger was invented (alledgedly).
After queuing for 30 min we got inside, after another 40 min we had a burger each and a small pot of potato salad.
The place is called Louis' Lunch and cooks burgers 'standing' on their side, kind of steamed. Between two slices of bread. No sauce. And seriously annoyed if you ask for ketchup. Well worth a visit!