mcron - cron in scheme

If you like scheme, and you like the Unix cron command, then consider mcron:

The new idea is to read the required command instructions, work out which command needs to be executed next, and then sleep until the inferred time has arrived.  On waking the commands are run, and the time of the next command is computed.  Furthermore, the specifications are written in scheme, allowing at the same time simple command execution instructions and very much more flexible ones to be composed than the original Vixie format.  This has several useful advantages over the original idea.

For Debian fans:
apt-get install mcron