Time.ly - Time.ly is a collaborative calendar solution for websites.
Google Calendar - Spend less time managing your day & more time enjoying it
CalendarX - Get a calendar your audience can follow
Simple Calendar - A simple calendar with events (optional recurring and reminders), week numbers and a customizable...
Campaign Calendar - Campaign Calendar by Bracket Labs builds a marketing calendar from your Salesforce Campaigns.
Calendar Lock PEA - Calendar Lock PEA is an encrypted desktop calendar with a day, week and month view. The shown calendars are never stored unencrypted on your disk, but exist only in the RAM. Platform-independent, Open Source, no installation or registration required.