The Google WordPress Themes resemble Google's minimal style and Google+ formatting. They aren't the most Web 2.0 looking themes, but they're the closest I've found to resembling Google's minimal formatting, and they're free.

Google WordPress Themes

1. WP Plus - Demo | Download (This WordPress template looks the best.)
   
2. Agent WP's Lab - Demo | Download
   
3. Reflex+ - Demo | Download (This WordPress template is extremely simple)