Session Based Working

In XP mail group, extremeprogramming@yahoogroups.com, while discussing the XP practice, '40-Hour-Week', Cory Foy mentioned about session based work:

We split the day into 4 "sessions". So we start with a 15 minute stand-up, have a 1.5 hour session, 20 min break, 1.5 hour session, lunch, 1.5 hour session, 20 min break, and a final 1.5 hour session.

That equates to about 6 hours of session time. However, because of the XP practices, and because everyone knows the schedules, they focus very hard on their sessions during that time, and we find ourselves amazingly productive. In fact, I'd say this is one of the more productive places I've been at."

I think it is a good idea. It makes developers more concentrated, focused and productive.
At the same time, this technique can be used for a personal sofware devolopment or any other kind of works.