Why can't it be 28x6? Now that our society has been transformed by mass production, division of labor, and artificial lighting, there is no longer any great advantage to being diurnal. There are, in fact, considerable advantages to breaking free of the 24 hour cycle.
Some of the benefits of extending the length of the day are relatively clear: you would simply have more time to do the things you wanted to do. Everything you do now in a typical day could be done for a little longer: you could sleep longer, work longer, spend longer blocks of time with your family and friends, and have more leisurely meals. Other benefits become apparent when you realize that "daily" activities would occur less frequently: only six times each week instead of seven. Work, for example, could be accomplished in larger blocks of time, with fewer trips to and from the work place.
