It's hard to get excited about a calendar app. I mean really what's to get excited about, but with that being said Fantastical has become one of my favorite and most useful apps. Fantastical adds a small calendar to the top bar of you Mac, since it shows the date this is also nice. The thing that makes Fantastical great is adding appointment to your calendar. Simply type what you want to add the way you would say it. In other words if I wanted to add an appointment I could type in there, "Meet Tricia for lunch this Friday at Season's of Japan in Savannah at 12." As I am typing this Fantastical is putting in my calendar.
I've used this app for a little less than a year now and love it. It works just as advertised and if you add a lot of appointments to your calendar it is a must have.