Harvard is as exclusive an employer as they are an educational institution. I have applied for a few positions there at different points, and usually get no response except for a rejection after a few weeks. That is not to say that they are not on top of their stuff, just very selective.
In this case I applied online, and got a call very quickly. We had a half hour telephone interview mainly to verify that I am conversant in all of the technologies that I have claimed. At that point we scheduled a on site interview for the next week, and we were off to the races.
At the on site interview I met with two engineers who asked most of the questions. They filled me in in further detail about what they do, and what they need. Then they quizzed me on how to resolve certain issues that I could face in this position.
Afterward the hiring manager took me to separately see two of his bosses. They interviewed me on much more general things that a nontechnical manager would care about. These interviews were reasonably short.
The two technicians took me to the cafeteria for lunch, which was certainly pleasant. Then we had another interview with a technician from another department that this team works closely with. The whole process took about four hours, and then I was done.
I followed up a week later, got my standard rejection from Harvard six weeks after that, and the position is still vacant as of this writing.