I used Christof Damian's calendar extension for displaying. I now have settled on a predefined 'article' format for the individual days. Then I wrote a Perl script (I am more comfortable with Perl than with PHP) that will check each day's article and notify me when an 'appointment' is due.
Hans, do you still have this Perl script? Would you mind sharing it - I would love to take a look at it! It'd be really awesome to have a reminder of upcoming or imminent events on the main page of the wiki, but I'm excited to see how your reminder system works.
btw: Do you happen to know whether the Calendar extension works flawlessly with MW v1.9? (I believe there were some issues with MW v1.8.2 before, so I'd rather ask before breaking anything... )
Thanks!
-- F.