What do you know about us?

This is actually a test. If you know very little, it is an indication that you are not very serious about working there.

Focus on them: Candidates who are really excited about the prospect of working there have done their homework. If you really want to stand out, learn more than what is listed on their web site.

Do some heavy research — perhaps find some articles on the company that not many would know about. It may even come up in conversation spontaneously, and you can show them a copy of the article.