Countdown+ - Countdown+ lets you to countdown to your events, birthdays, holidays and any events in your life. Add and Follow your friends and family events to keep track of their events.

MinuteTick - MinuteTick helps you stay on track by letting you set notifications for specific minutes of each hour.

Add-to-Calendar Button Generator - This open source projects lets everybody create amazing buttons, where users can add events to their calendars.

Cloxee: Countdown App & Widget - Cloxee is a free countdown app that allows to design your own countdowns, share them on social media and have them as the widget on your device.

Pretty Progress - Pretty Progress allows you to add beautiful & personalized Countdown & Progress Bar widgets on your iPhone's Home Screen.