I applied through other source. The process took 1 day. I interviewed at JCC Greater Boston (Westwood, MA) in Aug 2015
Interview
If you were a camper at Camp Grossman you can apply internally and be hired internally. If this is the case, there is no interview. For external candidates, I believe there is a phone interview with the camp director.
1 quick and easy interview with basic questions like what is your experience working with children. And how I would handle basic situations. After the 1 interview I got a decision within a couple days.