I had to come in for 2 in person interviews. The 2nd interview was basically the exact same as the first but with a different cast of interviewers. I never had to come back for another in person interview in my life and it didn't really add anything to the process. The CEO was there for both interviews as he is very micromanging and wants a "family" type environment.
I also had to write him an email in an essay type form of why I wanted to work there which was requested by the CEO. Again I have never been asked to do this in my entire life. I ended up getting the job so I guess it was worth the effort.