As teachers we have so many demands on our time and it is difficult to keep up with them all. Additionally, students are extremely busy in this day and age with multiple classes, after school programs, homework/projects due, etc. Once again Google Apps comes to the rescue with Google Calendar.
First if you are migrating from your district's system or an older online calendar, GCal will let you import pretty much any thing so you don't have to skip a beat.
You can even add a meeting from your phone with a text or get a reminder sent to your phone, which is incredibly useful when you are away from your computer.
My favorite part is that I never have my students asking what they missed when they were absent. I created a classroom calendar (you don't necessarily want to share your private calendar with everyone) and placed my curriculum schedule on it. I was even able to attach all of the necessary documents/notes to the day so when a student is away they can stay caught up at home or when they come back. Just make sure you share your calendar or place it on your website.
It is great for clubs or task groups where a small group of people need to create a meeting schedule. You can send a meeting invitation or reminders to the group.
Google Calendar is the the glue that binds all of the Google apps together. Getting anything done is made so much easier when you integrate GCal into your lifestyle.
If you would like a more in depth tutorial on any of the topics mentioned just leave a request in the comments.
On a side note, if you are struggling with all of the demands on your time I have a personal recommendation of David Allen's Getting Things Done: The Art of Stress-Free Productivity. It not only makes it easier to prioritize but allows you to find more free time than you would have ever thought you had.
The final post in this series involves Google Sites and the ability to share and exhibit your classroom to the world!