Links
Analytics
API
http://code.google.com/p/googlecl/ Command line tools for the Google Data APIs.
App Engine
http://code.google.com/p/app-engine-patch/ Use Django on App Engine - with lots of goodies
http://code.google.com/p/appscale/ Open Source Platform for Google AppEngine Apps.
Articles
Authentication
See Listing 3 from this article: Getting to know the Atom Publishing Protocol, Part 2: Put the Atom Publishing Protocol (APP) to work, The GoogleLogin scheme requires sending a simple HTTP POST to their authentication server.
Barcode
http://code.google.com/p/zxing/ Multi-format 1D/2D barcode image processing library with clients for Android, Java, and iPhone.
Calendar
Chart
Chrome
Code
Contact
http://blog.isotoma.com/2009/09/google-contact-api/ Google Contact API
Documents
Java
Core
Collections
Learning
Mail
Maps
http://cartographer.visualmotive.com/ Cartographer, Thematic mapping library for Google Maps.
Protocol
http://code.google.com/p/pubsubhubbub/ A simple, open, web-hook-based pubsub protocol and open source reference implementation.
Social
Apache’s OpenSocial Container Shindig and Apache Sling Are Now Friends
OpenSocial, OpenSocial.
http://www.google.com/friendconnect/ Lets you easily adding social features to your website.