The traditional 40-hour workweek calls for 8 hours of work per day for five days - Mondays through Fridays.
I've heard that some Corporate Cubicle Land type places have started offering workweeks that allow three-day weekends every other week. It calls for 9 hours of work on Mondays through Thursdays, then 8 hours or 0 hours on alternating Fridays.
Then there's my plan. 10 hours per day on Monday, Tuesday, Thursday, and Friday. Wednesdays off. It doesn't sound all that palatable at first glance, especially to those accustomed to the traditional five day workweek, because who wants to work 10 hours per day when 8 hours is already too long?
But it's not like that at all. First, it actually isn't a five-day workweek. It's 2 two-day workweeks with two "weekends." What that means is, I don't suffer the weekly mini-burnout encapsulated by the "Thank God It's Friday!" concept. At all. There's no time for it to set in because each workweek is over after two days. Those two extra hours per day aren't even noticeable.
Aside from the mental breaks, I'm also not trying to figure out how to cram odd errands around town into the beginnings and ends (and in many peoples' cases lunches) of the workdays. Those errands happen because many places aren't open on weekends, which means they must be done during a workday - but I don't have that problem because I have a full day to take care of them all at once on Wednesdays.
In short, I get a LOT more work done while I'm at work because I'm focused on work. I'm not distracted by other things I need to do, and my mind stays well-rested. My employers get more bang for their buck. Everybody wins. :)