Use Google Tasks in Calendar
Google Tasks can help you stay organized. Simply create a task and assign a due date.
Due dates are a helpful way to organize your tasks. Here's how you use them:
Create a task with a due date
Click on an empty space in Month view or in the All Day section and select the Task option.
Assign due date to existing task
Click the right arrow next to the task in question in the Task list. Then, click on the calendar icon to select a date.
Modify a task's date
Simply drag the task to a new date (as you would with a calendar event).
Mark task complete
Click on the checkbox next to the task.
Once your tasks have been assigned to calendar dates, keep track of what's due next by using the Sort by due date feature. To do so, click the Actions menu at the bottom of the Tasks gadget and select Sort by due date. While using this feature, you can reschedule a task by selecting it in your list, then pressing Ctrl+Up arrow to move it higher or Ctrl+Down arrow to move it lower.
To print a list of your tasks, click the Actions menu at the bottom of the Tasks gadget and select Print task list.