I applied online. The process took 1 day. I interviewed at ThinkTank Learning (San Francisco, CA) in June 2012
Interview
My interview was very brief (I believe because they needed a teacher for their classes starting in less than a week). It consisted basically of my going over what I typically teach and how long I've been doing it. Then finished off with my taking a few subject exams (biology, chemistry, and math, all high school level). I did very well so I was hired.
Interview questions [1]
Question 1
There were no unexpected or difficult questions. In fact, I didn't even realize it was an interview as they originally called me to come in to take some subject tests to see if I was qualified for the position. They then said I was hired on the spot.