I did this a few years ago. IN NYC, you go for three days, and if you don't get picked you are done.
However, I got picked on the afternoon of the last day. I then spent 5 days on a trial that involved a car accident and injuries. However, most of the 5 days were half days, or, sometimes only an hour, so I was probably only in the courtroom for no more than 15 hours. The cool thing was that at the time I was teaching High School and they said I "had" to take the whole day, because they were hiring a sub anyway. I had a lot of free time!
The case settled without us having to make any decsions. I thought both parties were full of crap and totally abusing the system.