Resolutions - A New Year's resolution a day until Christmas
Pocket Informant - Pocket Informant is the Best Calendar app for mac and iOS. Pocket Informant for iOS, Mac desktop, and Android.
Go Fucking Do It - Set a deadline and a price. If you fail, you pay.
Awesome Cal - Awesome Cal is a Calendar application for your iPhone that you can take anywhere and keep close by to monitor all the upcoming birthdays, festivities, meetings, and more from a single place.
Resolutz - Track Goals and Achieve Your New Year Resolutions
Fantastical 2 - Fantastical, the Mac calendar app you'll enjoy using. Quickly create new events with natural language input and more.