It's an interesting trend to spot - the upsurge in not only online calendars, but also widget like tools that allow you to plug a broad selection of events/dates into your personal calendarised life.
Do a search within your Google Calendar for "South African Holidays" or "Doodles" and you can add some nifty features to your online life.
These widget are available for Outlook as well. My favourite so far was sourced by Mr. Gray himself, obviously finding time between his vehement defence of 330Ci wallpapers available via WAP! :)
Click HERE to download the widget - run the file (it's safe, and zipped up for protectection), and you'll find all Tri-Nations, Super 14 games, F1, cricket world cup schedules neatly placed in Outlook - ready to sync to your mobile device.
Life is getting easier, isn't it? My girlfriend and I already use a "shared" calendar to keep up with work vs. social events. Friends from around the world, theoretically, can check it out before holding a party. They don't. But they could.
Social calendars. Shrink wrapped and ready to distribute.