William Van Hecke has an interesting idea for how to use his time. Based on a concept he read in a Neal Stephenson novel, he organizes his time in ten day periods:

Time is divided into ten-day decades. (We commonly use the word “decade” to mean ten years, nowadays, but prior to the 16th century, it could mean any collection of ten things, including days.) I love my desynchronized rhythms; the 10-day decade and the 7-day week create a healthy polymeter that drifts in and out of sync over time. At the start of each decade, I choose a template for how I’ll spend the next ten days worth of available time.

His days can be focused on five different themes: connect, read, study, create, or play. I love the idea, though I'm not sure I'd want to use the 10 day rhythm. If you like this article, his fuller picture of personal productivity can be found here.