Pretty standard In-N-Out - very busy, lots of people, and yummy burgers. Eating outside isn't too bad at night. It's a tad bit warm and will probably be the only spot you'd be able to find since finding available seating inside is almost impossible.
**For out-of-town visitors, there are a lot of cabs here so feel free to take a cab there, since there are plenty available for you to take back to wherever you need to go.