For one of my project I need to implement Google Event Calendar in my CMS. First time I thought its may be complicated. But its not. See this:
Step1: First you need a Google service account. If you already have Google account for Gmail or any other Google service then you can use that account ID, in that case you do not need any new account.
Step2: Login to Google Calendar by this http://www.google.com/calendar
Step3: After login you will see a default event calendar according to your account ID. To navigate other or create a new calendar go to screen left side My Calendars Panel Box. For create new calendar, click on create. For navigate other calendar you have to click on any one from the list of all your calendars. From list select your preferred calendar. After select your preferred calendar navigate to the calendar settings by click on small array. After click on small array you will see a drop down list. Click on Calendar Settings. You will see your preferred calendar settings. Here also you will see a block with titled Embed This Calendar. Copy the iframe code from here and paste the code on you required CMS page. All done.
[Note: Dont forget to set you calendar public from calendar settings, to access the calendar without login.]