Sleep Cycle - Bio-alarm clock that wakes you up at optimal times based on your sleep patterns.

ClocX - ClocX - freeware analog clock for Windows desktop with many features like calendar, alarms, skins, antialiasing and transparency.

Sleep as Android - Common alarm clocks ignore your sleep cycles, they wake you on schedule no matter your are currently in your deep sleep. Waking up from deep sleep is unpleasant, it makes you tired and it may negatively affect your productivity during the whole day.

LClock - Longhorn systray clock program

Sleep Time - Alarm Clock - Sleep Time provides insight into your sleep patterns. By tracking your level of movement throughout the night, Sleep Time generates customized sleep data in easy-to-read charts.

DS Clock - Keep your time synchronized with Atomic Time servers, using customizable digital desktop clock with westminster chimes.