Event at specific time

Is there a way to make an event happen at a specific time of day, but
which is effectively
taking no cpu time.

e.g. I want to display a message at 10:30 every day to say "Eat Banana"
or whatever.

Obviously the proce would need to be running, but in the background
taking virtually nil resources.

I could format two vars as time_hour & time_min and set a trace on
time_hour which is executed at 30 min intervals, and when 10 is
detected do the same for time_min at say 30 sec intervals.

BUT, there must be a better way, surely.

Regards, Niv.

.