Google has recently launched the iGoogle Artist Themes in collaboration with many designers/artists to create themes to personalize your Google homepage. As you land on the classic Google homepage you will see Jeff Koons' take on the Google logo and under the search bar a link that takes you to the iGoogle Artist Themes page. You can also "add your choice of news, email, games, and more for a page that's as useful as it is beautiful."
There are 68 artist themes choose from, to nam a few: Tezuka Osamu (Astro Boy), Jeff Koons, John Maeda, NIGO/BAPE, Marc Ecko and many more. If you have trouble choosing a theme you can try the sampler - "with this theme, you'll get to try out a new featured theme every day and decide whether you want to keep it."