I was contacted while in graduate school for a Material Science Engineering job that opened up. The First round of interview was informal with a meeting with my direct supervisor and another coworker. After I was notified by phone that I got to the second round of interviewing I was informed of what I would need to do to prepare for it. The second round/final round was more formal with a presentation that I gave regarding my graduate work and other work experience the company took me out to lunch with some of the other workers and I had some opportunity to ask questions and learn about the people/company informally. The presentation portion was about 30min with 10min of questions followed at the end by some 1:1 time with the local manager of the company.