Give a presentation!
Imagine that the interviewer is going to sit there and not say a word for the entire time. You should have a presentation about yourself to give him/her. Feel free to use the computer. Give a demo!
See Joel's comments at 43:24 in this transcript.
Spolsky writes: "What you need to do to prepare yourself against this contingency is say, "alright, if I have an hour with a person and the person just sits there and nods, what is the information I want to get across about why they should hire me? What are the things that I want that person to understand by the end of this interview and I don't want to leave the room without the person knowing that I've done these things, that I can do these things, that I'm good at those things, and maybe I'm not so good at those other things, maybe." You should have a plan of what you want to illustrate and why you're pretty good at it and maybe an explicit plan if there's something on your resume, if your grades are kinda low, but maybe not major, or if your grades were low freshman year but they got better after that and you want to explain that stuff, make sure that you know that when you go into that interview, "I need to get across to the interviewer in this hour these facts: this is why I got bad grades in freshman year;" or "I really love programming but I'm not so good at interpersonal skills;" or "I would really love a job where I could just hack all night long;" or "I've worked on this project and that project, or I built this thing." Make a list of those things that you want to make sure you get across. Practice with some friends and family. Call up your grandmother (I know she'd love to hear from you) and say, "Grandma, pretend you are a really bad interviewer. Just say, [high voice] 'So tell me about yourself,' [/high voice] and I'll do the rest." Just practice talking about yourself for an hour in a way which portrays yourself in a positive light and which highlights the accomplishments that you think will be relevant to that employer."
To be specific, you should be prepared to demo something you've written and explain it quickly, and be able to give a tour of a very detailed area that you worked on.
Example: I worked on a website called stackoverflow.com that's like a wikipedia dedicated to programmers. I implemented the "badges" feature which looks at certain metrics and then awards you badges. Some challenges were, how do we keep those metrics dynamic and not hardcoded in case the marketing monkeys wanted to add their own badges? Here's how we solved it and let me show how you can earn a badge!
Learn about their products and their company before you go! See if you can call and talk to a developer and ask him some questions beforehand. This is what a good sales person would do if they were selling to a company, and that is exactly what you are doing.