Starting this week, Google will begin adding Reminders to Google Calendar mobile apps, allowing you to easily see everything you have coming up. With this, you'll be able to view all of your calendars, as well as Reminders that you have set for yourself, all in one place. The Reminders will stick around, meaning if you don't complete them when they are scheduled to be completed, they will appear at the top of your calendar for the following day to ensure you get it done.
Like how events already show you additional details like addresses and such, Reminders will show you phone numbers and other important data that you will find useful. Reminders will still work across Google, so you can create them from Keep, Inbox and Google Now, and once created the events will show up in your calendar right away.
The new features will be rolling out this week, so be sure to keep your eye in Google Play for an update to Google Calendar.