Without giving too much away, I'll just say that my college uses one format for final exams, and is considering switching to another in a couple of years.
I've been thinking about the relative advantages of different formats, and would love to hear from my wise and worldly readers about their experiences with the different schedules. I'll admit being pretty agnostic on this one.
The various formats I've seen:
1. Run the regular class schedule right up to the bitter end; let each class schedule its own final, if any.
Advantages: No schedule conflicts, no issue with some classes preferring papers or projects instead of exams.*
Disadvantages: Doing 'common' finals across multiple sections of the same class becomes impossible, and exams are limited to the length of a class period.