Stack Overflow
Q&A for professional and enthusiast programmers
Bicycles
Q&A for people who build and repair bicycles, people who train cycling, or commute on bicycles
Board & Card Games
Q&A for people who like playing board games, designing board games or modifying the rules of existing board games
Area 51
Stack Exchange Network staging zone, where users come together to build new Q&A sites
Server Fault
Q&A for professional system and network administrators
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems.
Photography
Q&A for professional, enthusiast and amateur photographers
Game Development
Q&A for professional and independent game developers
Android Enthusiasts
Q&A for enthusiasts and power users of the Android operating system
English Language & Usage
Q&A for linguists, etymologists, and serious English language enthusiasts
User Experience
Q&A for user experience researchers and experts
Meta Stack Overflow
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Stack Apps
Q&A for apps, scripts, and development with the Stack Exchange API
Programmers
Q&A for professional programmers interested in conceptual questions about software development
Robotics
Q&A for professional robotic engineers, hobbyists, researchers and students
Motor Vehicle Maintenance & Repair
Q&A for mechanics and DIY enthusiast owners of cars, trucks, and motorcycles
The Great Outdoors
Q&A for people who love outdoor activities, excursions, and outdoorsmanship
Answers OnStartups
Q&A for entrepreneurs looking to start or run a new business
Raspberry Pi
Q&A for users and developers of hardware and software for Raspberry Pi
Parenting
Q&A for parents, grandparents, nannies and others with a parenting role
Personal Finance & Money
Q&A for people who want to be financially literate
Christianity
Q&A for committed Christians, experts in Christianity and those interested in learning more