[expert] cron stuff

[Vic]

I wonder how you make your cron daemon do things
in less increments than just on the hour?

I can make my system play a sound (a bong) to strike
the hour by putting play bong.wav in my 0anacron
file in the cron.hourly directory, but I want to
have some other things happen like maybe every
30 minutes or on specific dates like appointment
reminders if this is possible.

Thanks

Vic