http://googlesystem.blogspot.co.uk/2012/10/a-new-youtube-ui-experiment.htmlHere's how you can try the new interface. If you use Chrome, Firefox, Opera, Safari or Internet Explorer 8+:
1.
open youtube.com in a new tab2. load your browser's developer console:
* Chrome - press Ctrl+Shift+J for Windows/Linux/ChromeOS or Command-Option-J for Mac
* Firefox - press Ctrl+Shift+K for Windows/Linux or Command-Option-K for Mac
* Opera - press Ctrl+Shift+I for Windows/Linux or Command-Option-I for Mac, then click "Console"
* Safari - check this article
* Internet Explorer - press F12 and select the "Console" tab.
3. paste the following code which changes a YouTube cookie:
document.cookie="VISITOR_INFO1_LIVE=jZNC3DCddAk; path=/; domain=.youtube.com";window.location.reload();
4. press Enter and close the console.
To go back to the standard UI, follow the same steps, but use the following code:
document.cookie="VISITOR_INFO1_LIVE=; path=/; domain=.youtube.com";window.location.reload();