Many people swear by polyphasic sleep, or the idea of taking frequent naps throughout the day as opposed to sleeping in one long chunk. Leonardo da Vinci was one of the most notable proponents of this seeping method, noting that it helped him be more productive throughout the day. This alarm clock concept follows da Vinci's 3.5 / .5 sleep schedule, meaning that an alarm will sound every 3 hours and 30 minutes indicating that it is time for a nap. Another alarm will sound a half hour later, indicating that it is time to wake up again.
All-in-all, the da Vinci Sleep alarm clock will net you around 3 hours of shut-eye per day (although I have heard da Vinci slept even less than that). Obviously, a schedule like this isn't for someone who maintains a regular 9 to 5 schedule, or operates heavy machinery—but it would be perfect for bloggers, retired persons and the unemployed. This particular clock is only a concept, but you could set a regular alarm fairly easily to try this sleep method yourself. [Yanko]