Sesame – new awesome feature from google.

Go to the link, use your phone to scan the QRcode on the page and hit the resultant url – the desktop browser will automagically redirect to your logged-in gmail without entering your password. You are in!

We constantly experiment with new and more secure authentication mechanisms, and it looks like you found one of our experiments. Note that this feature is not officially supported and may go away at any time – we’re already working on something better.
Dirk Balfanz, Google Security Team.

Best solution for public/unsecure workstation. Go Google!