Of course, a calendaring system is no good without a good supply of events. Spare yourself the webmaster bottleneck by farming out event creation to other contributors. Just remember to give them these three tips so your site-wide calendar (and any others you make) are consistent and easy to understand:
Name events globally. It makes sense for the president of the Parcheesi club, adding a night of Parcheesi-filled fun within his own club folder, to name it "Open Play". However, that title doesn't work so well on the site-wide calendar: play of what? Make sure your event contributors understand that "Open Parcheesi Play" is a better title. In addition to making the calendar clear, it will also net visitors more hits when they search for "Parcheesi".
Keep dates out of titles. Because no one can ever get enough Parcheesi, the club offers weekly sessions. It can be tempting, while working in the club's own folder, to differentiate the sessions by adding dates to...