What are some good questions to ask current graduate students when visiting schools? For the record, I'm visiting the University of Chicago as an accepted PhD student (in the geophysical sciences) next week.

In particular, I'd especially appreciate creative questions that few other visiting students ask.
You'll want to get a sense of their feelings for:


The graduate program


Easy to work with regarding customizing the program to their specific needs (i.e., taking courses outside their specific area if necessary)?
How easy/difficult was the process for joining a lab?
Have they found the staff easy/hard to work with?

The advisor


Attitude towards students (respectful/distant/slavedriver)
Presence in the lab (micromanager/occasional presence/absentee)
How organized is the research?

The university as a research institution


Easy collaboration between departments (in their opinion)?
Availability of course offerings (from their experience)?

The city as a place to live