A daemon that initiates other programs at specific times, as indicated by a pattern. Ships with just about every Linux distribution, and is available from the 'net.
Installation is trivial.
It's very small, under 100 Kb. Repetitive, production processing. Backups, cleanups, purges, merges, or other housekeeping tasks. Things you might forget, but are essential to the health of the system. A daemon that runs all the time, checks time specification files every minute, runs as root.