The first interview was at my University. It was your typical 45 minute face-to-face whiteboard coding style interview. During the first five minutes, my interviewer introduced himself and asked me questions about myself. Be prepared to talk about yourself and your resume. The next 35 minutes were spent entirely on 1 question. After arriving at a naive solution, I fined-tuned and optimized my code. The last 5 minutes were reserved for any questions I had.
I passed the first interview, and went on to the second interview. The flew me down to HQ. This interview went horribly. The question was more difficult than the first interview, and my interviewer's accent made him difficult to understand. After the interview, I toured Facebook's campus and had lunch, etc.