What if they ask you "Do you have any more questions?" multiple times? During my interview today I asked 3 - 4 good, detailed questions during the interview, so when he asked at the end I didn't really have anything else to ask. What's the best thing to do then?
I've tried keeping one question as a "final question", but sometimes that doesn't work.
With the "Is there anything else you'd like to cover" question its just a catch-all in case you forgot to talk about something. So have a list of every activity/award you would want to talk about. I usually tie a couple of my extracurriculars together, or talk about one ec that I don't always mention, and say I want to do something like that in college. I think the "talk about your interest" idea is a good one too.
Even it feels like you're bragging, at some point you have to get over it and say "I am really excited/passionate about/intrigued/interested in X, and I have done this, and it has been a learning/intellectual/fascinating experience for me."