Google's latest easter egg is a search for [let it snow] where it will begin snowing on the search results screen, so much so that the results will begin to be covered by the white flakes, making it impossible to see the results.
You can then use your mouse to clear away the snow to see the results, or you can hit the "defrost" button, which is converted from the search button.
Click here to see it in action.
Here is also a video:
I should note that this won't work on older browsers. Which is why some people are complaining.
Forum discussion at Google Web Search Help and Google+.
Image credit to ShutterStock for a snowflake image.