I've recently been giving my class wiki a bit of a re-vamp (always a work in progress!) and one of the latest additions is a Google Calendar. I already had one of these, showing important dates for the class, trips, deadlines etc. on a page of its own.
The difference is that the new one is on the Navigation bar of the wiki, and shows the 'Agenda' format, listing just that day's events and when they are happening. This makes the daily timetable accessible, no matter which page of the wiki they are using.
This is how I did it:
The great thing about a Google Calendar is that you can have one off events, or have them repeat weekly or daily, which means that once it is set up, it just needs a little tweaking here and there.
Try adding one to your wiki sidebar, it's a good way to keep everyone informed. And now I don't have my students saying, "What are we doing after lunch, Mr Mac?!"