iCal - share your events with your friends and see your friend's calendars.
MenuCalendarClock iCal gives you instant access to your iCal calendars from a menu bar icon.
Manage events and reminders from your Mac's menu bar.
Sync contacts and calendars with your Mac computer.
Alternative to Apple's iCal birthday calendar that has a range of features that has made it indispensable for many iCal and Address Book users.