I find this part of an interview challenging. You talk for an hour, describe your qualifications, hear about the job, and all of a sudden you're at the end and they say, "So do you have any additional questions for me?" I freeze up! Generally by that time I've asked or had answered all my questions, in the conversation. I know it's a good idea to ask something intelligent-sounding at that point, but often I just conclude with a lame "No I think you've answered everything already, thanks."
Seems like being prepared with a few ideas would be smart. Anybody have any suggestions?