Simple Calendar is the most beautiful, highest-rated calendar app on Windows Phone, and it's free!

See more from your calendars at a glance. The Simple Calendar live tile shows up to three appointments, and the month view shows all of the day's appointments underneath. Look at the whole month and still know where you should be in an hour - just double-tap a day to create a new appointment.

Simple Calendar uses your existing calendars, so there's nothing to set up, and your personal data never goes to our servers.

-Easy to use, no setup required
-App doesn’t send any data to our servers
-Beautiful and simple design
-Beautiful, simple month and week views
-Easily add an appointment by double-tapping on a day in the month view or a time in the week view
-Easily jump to today's date by tapping and holding on the calendar
-Month view lets you see all the appointments for a particular day
-Multiple appointments on wide and medium live tiles
-Option to use transparent background
-Option to hide all day appointments on the live tile after a certain time of day (you customize the time you want)
-Options to customize live tile appearance

This app is free, but advertisements will show up after 7 days of use. You can remove the ads with an in-app purchase. Also, there are other in-app purchases, like additional live tile options. In-app purchases are tied to your Microsoft Account, so if you aren't seeing a feature you paid for go back into the "buy features" page and you can download the feature again for free.