I want this digital zen travel alarm clock. It strikes a metal bar tuned to make a single B note. If you don't switch it off, it stikes it again in 3 minutes and 48 seconds. And then again in 2 minutes and 21 seconds. And again in 1 minute and 28 seconds, and so on until it will ring every 6.5 seconds.

You can also set it to strike a single note every hour on the hour. I like that.