Stack Overflow
Q&A for professional and enthusiast programmers
Law
Q&A for legal professionals, students, and others with experience or interest in law
Role-playing Games
Q&A for gamemasters and players of tabletop, paper-and-pencil role-playing games
Super User
Q&A for computer enthusiasts and power users
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
Science Fiction & Fantasy
Q&A for science fiction and fantasy enthusiasts
Web Applications
Q&A for power users of web applications
Movies & TV
Q&A for movie and TV enthusiasts
English Language & Usage
Q&A for linguists, etymologists, and serious English language enthusiasts
Personal Finance & Money
Q&A for people who want to be financially literate
Ask Different
Q&A for power users of Apple hardware and software
Anime & Manga
Q&A for anime and manga fans
Code Golf
Q&A for programming puzzle enthusiasts and code golfers
Arqade
Q&A for passionate videogamers on all platforms
History
Q&A for historians and history buffs
Cross Validated
Q&A for people interested in statistics, machine learning, data analysis, data mining, and data visualization
Meta Stack Exchange
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
Database Administrators
Q&A for database professionals who wish to improve their database skills and learn from others in the community
Ask Ubuntu
Q&A for Ubuntu users and developers