Google is very well known for these kind of neat tricks, or "Easter Eggs". We all remember the "tilt" search "Easter Egg" where the window of the browser tilts. Now it is "let it snow" which as you can imagine virtual snow starts to fall.
Search "Tilt" Easter Egg
Just head over to Google and search "Let it Snow" and watch the snow fall. The "search" button will change to defrost because as the times past the window will get frozen. It is pretty neat and it also works on the iPad (check iPad screenshot below).
Watch the snow fall and freeze the screen
Press "Defrost" to clean up the window
Try it out, let us know what you think.