Google Docs Data APIs - join
Welcome to the official Google Documents Data API developer discussion group! This is a forum dedicated to the exchange of information and opinions related to the following APIs: Google Spreadsheets Data API Google Documents List Data API
Low activity, 1298 members

Google Labs - Code Search - join
This is a discussion forum for Google Code Search where you can exchange ideas and information with other Google Code Search users.
Low activity, 1542 members

Google Web Toolkit Contributors - join
This group is for interested developers to discuss Google Web Toolkit internals and contribute bug-fixes and enhancements. For more information, see: http://code.google.com/webtoolkit/makinggwtbetter.html
Medium activity, 1190 members