Google Calendar is the official Google calendar tool, it lets you note down any date or event on your virtual calendar, and then receive a notification when you near the chosen date.
The best part of Google Calendar is that, like all Google applications, it lets you synchronize it with the rest of the services provided by this internet giant. The result is that you can easily and quickly create notes and events, plus you'll never miss an appointment ever again.
Among the options offered by Google Calendar you'll find the option of customizing certain events by using different colors, or sending an email to all those taking part in an event. You can, for example, make sure every member of the office receives a reminder email the day of an important meeting.
Google Calendar is an indispensable application for any Android device user, and is usually included by default in just about all of them. Never forget anything ever again.