"So what questions do you have for me?" is something you will be asked in 99% of all your interviews, and you need to be able to fire back with at least two thoughtful and relevant questions.
One great question that was brought up by a student when I spoke at Cal Poly Pomona was "Are there any concerns you have about me being a good fit that I can address?". This gets to the heart of what you want to know and allows you to recover from anything that the interviewer might see as a weakness or red flag. This may throw the interviewer off so give them a second to think about it and make sure you respond by addressing their specific concern.
Ask about specific things at the company, such as the company culture, most important things for someone in this position to achieve, what a day in the office would look like, and the biggest challenges the department faces. These questions are very specific and will tell you a lot about the company and the role. These questions also show that you are serious about the opportunity and very interested
You should always end an interview with "When can I expect to hear back from you?" or "What are the next steps in the interview process?".
While you may think its funny to ask "So do I start tomorrow", its not, don't say that.
What are some good questions you've asked the interviewer? Let me know in the comments.