incron - This program is an "inotify cron" system. It consists of a daemon and a table manipulator.
ClocX - ClocX - freeware analog clock for Windows desktop with many features like calendar, alarms, skins, antialiasing and transparency.
fcron - Fcron is a scheduler designed for Unix/Linux systems, especially usefull when your system is not up all the day long.
LClock - Longhorn systray clock program
Anacron - Anacron is a periodic command scheduler. It executes commands at intervals specified in days.
DS Clock - Keep your time synchronized with Atomic Time servers, using customizable digital desktop clock with westminster chimes.