Google Fun.

Just to bring a light touch of humour and pleasure to everything Google, there are some websites which I think are worth visiting.
Googlefight.com is a site that turns guessing which keyword has more search results into a game.
The objective is simply to choose two keywords (presumably one from each of two different people who are competing) and submit them to see which one is more popular. The less graphical Google Battle is also fun.

Googleguide.com is another great which informs the user about many of Google's products. Definitely worth a look.
55 ways to have fun with Google is a bit of fun in regard to Google.Full of games, jokes, and ideas.
Google Earth Hacks shows some great places to look using Google Earth.
Guess the Google is a great little game that presents you with a grid of 16 related images. Your goal is to determine the search term that generated this list of images.
You’ve got 20 seconds to guess as many times as you can. You’ll receive 20 points for each correct answer plus additional points for guessing quickly.