Just some guy having too many accounts on too many sites (and most of those I can't even remember ;-)
English Language & Usage
Q&A for linguists, etymologists, and serious English language enthusiasts
Stack Overflow
Q&A for professional and enthusiast programmers
Writers
Q&A for authors, editors, reviewers, professional writers, and aspiring writers
Meta Stack Overflow
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
German Language & Usage
Q&A for speakers of German wanting to discuss the finer points of the language and translation
Christianity
Q&A for committed Christians, experts in Christianity and those interested in learning more
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
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
Sports
Q&A for participants in team and individual sport activities
Android Enthusiasts
Q&A for enthusiasts and power users of the Android operating system
Linguistics
Q&A for professional linguists and others with an interest in linguistic research and theory
Electrical Engineering
Q&A for electronics and electrical engineering professionals, students, and enthusiasts
Mathematics
Q&A for people studying math at any level and professionals in related fields
Physics
Q&A for active researchers, academics and students of physics
Stack Apps
Q&A for apps, scripts, and development with the Stack Exchange API
User Experience
Q&A for user experience researchers and experts
Bicycles
Q&A for people who build and repair bicycles, people who train cycling, or commute on bicycles
Mi Yodeya
Q&A for those who base their lives on Jewish law and tradition and anyone interested in learning more
Game Development
Q&A for professional and independent game developers
Photography
Q&A for professional, enthusiast and amateur photographers
TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
Programmers
Q&A for professional programmers interested in conceptual questions about software development
Database Administrators
Q&A for database professionals who wish to improve their database skills and learn from others in the community
Spanish Language & Usage
Q&A for students, teachers, and linguists wanting to discuss the finer points of the Spanish language
Personal Finance & Money
Q&A for people who want to be financially literate
Graphic Design
Q&A for professional graphic designers and non-designers trying to do their own graphic design
Martial Arts
Q&A for students and teachers of all martial arts
Russian Language & Usage
Q&A for students, teachers, and linguists wanting to discuss the finer points of the Russian language
Biblical Hermeneutics
Q&A for professors, theologians, and those interested in exegetical analysis of biblical texts
Japanese Language & Usage
Q&A for students, teachers, and linguists wanting to discuss the finer points of the Japanese language
Personal Productivity
Q&A for people wanting to improve their personal productivity
Musical Practice & Performance
Q&A for musicians, students, and enthusiasts
Audio-Video Production
Q&A for engineers, producers, editors, and enthusiasts spanning the fields of audio, video, and media creation
LEGO® Answers
Q&A for LEGO® and building block enthusiasts
Cryptography
Q&A for software developers, mathematicians and others interested in cryptography
Answers OnStartups
Q&A for entrepreneurs looking to start or run a new business
French Language & Usage
Q&A for students, teachers, and linguists wanting to discuss the finer points of the French language
Role-playing Games
Q&A for gamemasters and players of tabletop, paper-and-pencil role-playing games
