Ask them what you're interested in knowing. Stuff like details about the curriculum, experiential education, where graduates usually go for jobs, what their opportunities are, and if the school is developing new programs, you could ask about where those programs are headed.
If you read some information from the website and then ask them questions about stuff that isn't listed, it'll be a good start. I think it will be good to show them that you're interested in what's going on at the school.