Google Open Source - All of Googles open source projects under a single umbrella
Mars Colonies - A free old-school RTS... on Mars
LaunchKit - Open Source - A popular suite of developer tools, now 100% open source.
The Evolution Of Webdesign - See how one webpage has evolved since 1991
Code NASA - 253 NASA open source software projects
HACKTIKA - Fill your Growth Idea Backlog by the Best Growth Hackers