I have a student currently that when ever I ask for questions will always want to talk about something completely off topic. Almost every time. He's not being mischievous, just the way his mind works. I often enough say "lets stay on the topic at hand", or "stay after class and we can discuss it". When i do answer his questions i end up 2 miles down the road in the wrong direction. The rest of the class groans every time he asks one of these and I need to move along. How do other people deal with these types of students?