Google is now offering an online demo of their new Presentations platform. This demo does not require you to login.
You can play around with the service and even share the test presentations with your friends to test live collaboration.
Google is still releasing this new edition to all the users of Google Docs.
The company said:
Check out the new animations and transitions, get artsy with drawings, and show off your masterpiece to a friend or colleague. You can share the link in the demo with others and work on the same presentation together. No login required. No Google account needed. Just go to docs.google.com/demo to take it for a spin.