Basically, yes. You can configure most cron program to mail task output to you (it’s usually done by setting the MAILTO variable in the crontab, provided sendmail is available on your system).

So basically, I do things like:

0 9 11 10 echo 'lunch with John Doe at 12:20'

It sends me a mail, and I can see the upcoming events with crontab -l. If it’s not a recurring event, I then delete the rule.