Programming is fun.
See my GitHub profile for, among other things, a list of SE posts that turned into open source contributions.
Stack Overflow
Q&A for professional and enthusiast programmers
Super User
Q&A for computer enthusiasts and power users
Worldbuilding
Q&A for writers/artists using science, geography and culture to construct imaginary worlds and settings
Science Fiction & Fantasy
Q&A for science fiction and fantasy enthusiasts
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
Mathematics
Q&A for people studying math at any level and professionals in related fields
Academia
Q&A for academics and those enrolled in higher education
English Language & Usage
Q&A for linguists, etymologists, and serious English language enthusiasts
The Workplace
Q&A for members of the workforce navigating the professional setting
Aviation
Q&A for aircraft pilots, mechanics, and enthusiasts
Space Exploration
Q&A for spacecraft operators, scientists, engineers, and enthusiasts
Astronomy
Q&A for astronomers and astrophysicists
Personal Finance & Money
Q&A for people who want to be financially literate
Puzzling
Q&A for those who create, solve, and study puzzles
French Language
Q&A for students, teachers, and linguists wanting to discuss the finer points of the French language
Russian Language
Q&A for students, teachers, and linguists wanting to discuss the finer points of the Russian language
Writing
Q&A for the craft of professional writing, including fiction, non-fiction, technical, scholarly, and commercial writing
Physics
Q&A for active researchers, academics and students of physics
Graphic Design
Q&A for Graphic Design professionals, students, and enthusiasts
Information Security
Q&A for information security professionals
History of Science and Mathematics
Q&A for people interested in the history and origins of science and mathematics
Home Improvement
Q&A for contractors and serious DIYers
Bricks
Q&A for LEGO® and building block enthusiasts
Literature
Q&A for scholars and enthusiasts of literature
Robotics
Q&A for professional robotic engineers, hobbyists, researchers and students
Board & Card Games
Q&A for people who like playing board games, designing board games or modifying the rules of existing board games
Seasoned Advice
Q&A for professional and amateur chefs
Lifehacks
Q&A for people looking to bypass life's everyday problems with simple tricks
Computational Science
Q&A for scientists using computers to solve scientific problems
Artificial Intelligence
Q&A for people interested in conceptual questions about life and challenges in a world where "cognitive" functions can be mimicked in purely digital environment
Retrocomputing
Q&A for vintage-computer hobbyists interested in restoring, preserving, and using the classic computer and gaming systems of yesteryear
Engineering
Q&A for professionals and students of engineering
Arduino
Q&A for developers of open-source hardware and software that is compatible with Arduino
The Great Outdoors
Q&A for people who love being outdoors enjoying nature and wilderness, and learning about the required skills and equipment
Code Review
Q&A for peer programmer code reviews
Server Fault
Q&A for system and network administrators
Geographic Information Systems
Q&A for cartographers, geographers and GIS professionals
Stack Overflow на русском
Вопросы и ответы для программистов
Cross Validated
Q&A for people interested in statistics, machine learning, data analysis, data mining, and data visualization
TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
Code Golf
Q&A for programming puzzle enthusiasts and code golfers
MathOverflow
Q&A for professional mathematicians
Travel
Q&A for road warriors and seasoned travelers
Meta Stack Exchange
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Electrical Engineering
Q&A for electronics and electrical engineering professionals, students, and enthusiasts
Signal Processing
Q&A for practitioners of the art and science of signal, image and video processing
Earth Science
Q&A for those interested in the geology, meteorology, oceanography, and environmental sciences
Open Source
Q&A for people organizing, marketing or licensing open source development projects
Software Engineering
Q&A for professionals, academics, and students working within the systems development life cycle
Interpersonal Skills
Q&A for people looking to improve their interpersonal communication skills
Bioacoustics
Q&A for people interested in the studies of non-human animal sounds and the impacts of sounds on animals
Area 51
Q&A for proposing new sites in the Stack Exchange network