How do you think the FBI and the CIA find people to work for them?

You know I would say the old thing about getting the smartest people that come out for college to work for them, but in today's world I am sure that they have moved beyond that. Is it possible that they have people that look for different future agents in all categories of life. For instance if you where any extremely smart person, but you could only display that intellect on the computer do you think the FBI or CIA might show up at your house one day and ask you if you wanted to work for them? Give me your thoughts.