Google Chrome has a feature that you have probably never seen: a dinosaur game that only becomes available when you lose internet.
To access the game, switch off your wireless connection, try and load up a page, and wait for the "unable to connect to the internet" page. From here, just tap the spacebar and the game starts.
Just like Canabalt, the T-Rex game is an endless runner with the obstacles becoming harder and harder to navigate as the game goes on.