Here are some examples of on-line community calendars (if you know an especially good one, please click on "e-mail" and tell us about it).
http://www.floridatrend.com/calendar.asp (Florida Trend)
http://pbccc.org/index.cfm?fuseaction=events.list& (PBC Arts Council)
http://www.mychurchevents.com/calendar/calendar.aspx?ci=L6I3M7J4G1F0O9N8H2 (St. Gregory's calendar)