I'm sure it depends on the school. At my school there are two major hosptials that most of the rotations are done at. The first is the county hospital, the second is at the VA. There is another large private hospital near the downtown area which also handles a fairly large indigent population that a smaller number of students do rotations at.
We usually switch inpatient services half way through each rotations. Example: medicine I did the first month at the county hospital, the second month at the VA. Surgery here everyone does 2 weeks of trauma (at the county hospital), then the other two weeks of that month are done at one of 3 private hospitals (one a children's hospital, the other two in suburbia). The second month of surgery is at either the county hospital, the VA or the large private hospital. The OB month of OB is done at the county hospital for everyone, with the gyn month at either the county hospital, the large private hospital or one private hospital in suburbia.
Grades for clerkships generally are based primarily on your clinical performance, plus the grade on one of the standardized "shelf" exams for that area. Surgery adds an oral exam. The exact breakdown of weights of the clinical evaluations vs exams varies with the clerkship, but the clinical evaluation is always >50% of your grade.
