Sleep Cycle alarm clock: "The Sleep Cycle alarm clock, developed by Swedish developer LexWare Labs AB, is a bio-alarm clock that analyzes your sleep patterns and wakes you when you are in the lightest sleep phase.
Waking up in the lightest sleep phase feels like waking without an alarm clock - it is a natural way to wake up where you feel rested and relaxed.
Sleep Cycle has become a huge success with a #1 paid app position in many countries, including Germany, Japan and Russia."