The best single thing you can do to reduce working fatigue is to minimize your commuting time. If you commute an hour each way to work, then over a five day week, you've racked up an extra 10 hours -- not to mention the extra expense, and the aggravation periodically inflicted by traffic jams or public transport problems -- and the worst part of it is that it's mostly dead time. (I'll make an exception for commuting to work on foot or by bicycle, as part of an exercise regime.)
But yeah, I commute for 3h a day and it sucks. Haven't thought up a good solution yet, since I really don't like the city where I work.
I've considered it, but I know my productivity sags at the 8 hour mark as it is, so I don't think it's a good fit for me or the company.
Also, it often drops after lunch, but this also depends on when we have lunch. It's significantly worse if we have lunch around 12:00 than around 13:30-14:00. Our research group loves to go at 11:30 (!!!) which destroys the whole day for me, so a few of us have just stopped eating together with them.
Update: I've added a poll: http://news.ycombinator.com/item?id=2052007
"Twenty-three percent of Dutch men have reduced hours, compared to 10 percent across the European Union and in the United States; another nine percent work a full week in four days."