I'm gonna assume you're talking about pathology rotations
At University of Michigan we have a one month rotation in pathology. It is fairly flexible and students are free to sit in on signouts in the mornings and/or afternoons.
For instance, before Michigan switched from general to subspecialized signout, we had several general signout rooms such as Room 1 and Room 2. I spent a week in each room. Signout generally went from 8-12. Students were allowed to come in at 9 am though. The general atmosphere was laid-back, relaxed, but educational depending on the attending who was signing out the slides. In the afternoon, we had the option of doing whatever we wanted. We could either go home, attend other signouts (such as Gyn or derm signout), do autopsies, or tour around the clinical labs (micro, clinical chem, heme).
Another week was dedicated to hanging out in the autopsy area. The week I did autopsy, there were only a few autopsies. Thank god I didn't have to do an autopsy with yaah since I heard that he works you like a mofo!
The fourth week is pretty flexible. You can do whatever you want that week. I went back to Room 1.
I must add that at Michigan, nobody is gonna make you gross. Basically you are an observer who sits in on signout and observes other stuff. If you wanna get some grossing experience, you need to be proactive...and the PAs are really nice about getting you some hands on experience. Furthermore, you can be proactive about being involved in previewing slides. However, as a student, you will most likely just get in the way of the resident's work. The residents have quite a few cases to go through and I figure that they don't need many other distractions.
At the end of the rotation, you turn in a paper or do a talk. All of us did a talk since it was easy to prepare. Quite a few path attendings attended the seminar hour were all 6 of us gave a 15 minute talk. We made our talks interesting but also entertaining and the environment was very laid back and fun.
If you would like to do an away rotation at Michigan, I do know that it is possible. I know of one person who did an away rotation here the month before I did my path rotation. If you would like to try to sign up, you will need to get in touch with Joe Fantone to set up the rotation.