Re the "trivia guy" that mray mentioned: I'm that guy, and I'm looking to see if you actually did the work you describe on your resume. I may not know anything about the topic (although I try to pick something that I do know or at least have some exposure to), I just want to see if you can talk intelligently about it. And by "intelligently," I mean the what, why, and how: why did you do what you did, and how did it improve what you were working on.

This is not the "trivia guy" that Joel mentions.