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