Google added a few new features to the project hosting wiki on Google Code: 

• You can now add a 'Wiki sidebar' by specifying the wiki file that describes your side navigation in the Administration tab under Wiki settings.
   
• side navigation is added across wiki pages (e.g doctype docs) to improve navigation from one wiki page to another.
• add a generated table of contents. To add a table of contents, just copy the following syntax to your wiki page.

  <wiki:toc max_depth="1" />

  Finally, to improve the style of your wiki pages, added some html support. For more information on what html is supported, take a look at the documentation.