Chances are, if it was between 2:20 and 3:50, you were sleeping. Between those times, the greatest number of people in America are sleeping, at 95%. That was by far the highest percentage of people doing the same thing at the same time at any point in the day. Next highest was from 10:20 to 11:00 when 33% of people were working.
You can glean these and many other fascinating tidbits from this captivating chart from the NYT.