Three Day Weekend
I've long thought that I would prefer a 40 hour work week in four 10 hour days over the more typical five 8 hour days. I think a lot of people would be more productive that way. Of course, there are lots of jobs (like my current one) where this isn't very realistic, but I think most people dismiss the concept too quickly. Check out both of these articles:
The Case for a Four-Day Work Week on Inc.com (via LinkedIn)
More school districts trying four-day weeks to save money on PRI
Part of what started my interest in non-traditional schedules was my time at Cornell College. They use a block schedule for all of their classes. Each block is three and a half weeks long, and you can take nine blocks per year. It isn't for everyone, but it can be great.
One side effect of this is the block break. Each block ends on a Wednesday, and the following block doesn't start until Monday, so once every four weeks you get a four day weekend. Having seen what can be accomplished on this sort of schedule I'm surprised more schools and companies aren't experimenting with similar options.