First, sorry for the last post, I was wrong. Thanks Lee Jarratt for your comment.
And now, here's how you can enable the experiment:
- Open Chrome and install this extension.
- Go to http://googleads.g.doubleclick.net/. You'll see an error 404, it's normal. Select "Edit Cookies" option on the context menu.
- Find a cookie named "id" and replace the value with this cookie value:
- Click "Submit cookie changes". You'll see the experiment (example).