Launch the LiveSlides app.
Open a presentation in Keynote.
Go to the Google Calendar website.
You'll need to make your calendar public by following these directions.
Copy the URL from your browser.
Paste the URL into the LiveSlides dialog and click "Insert".
A new slide with a placeholder image will appear at the end of your presentation. Drag the slide to where you'd like to display the web content.
Click the Play button to view the live web content in presentation mode.
Choose your operating system for instructions on inserting Google Calendar into PowerPoint on Windows or Mac.