What to ask Professor

[spartacutor]

Hello everyone, 

This friday I will be attending an open-house event organized by one of the school I've been accepted into. It's one of my top choices and I've already had a phone call with a professor previously. I will have the chance to meet 1on1 with this professor who works at the research center I would like to join as well as the director of that research center.

I already have a few ideas what to ask them but was wondering if anyone had some thoughts on what I should ask or discuss with them.

Thanks!