We recently saw video of a brand new YouTube user interface that Google is testing with some users.

You can now access it yourself by changing the cookie in your browser. Here is the exact value of the cookie:

document.cookie="VISITOR_INFO1_LIVE=Gapj9bz_H8M; path=/; domain=.youtube.com";window.location.reload();

In Chrome you need to load YouTube.com in a new tab and press Control+Shift+J to get to the console where you need to paste this and press enter. Other browsers have similar features.