Software development and computer science for the win!
See my web site for the kinds of stuff I play with: http://nayuki.eigenstate.org/
Career profile: http://careers.stackoverflow.com/nayuki
Q&A for professional and enthusiast programmers
Q&A for students, teachers, and linguists wanting to discuss the finer points of the Japanese language
Q&A for professional, enthusiast and amateur photographers
Q&A for people studying math at any level and professionals in related fields
Q&A for professional programmers interested in conceptual questions about software development
Q&A for people who want to be financially literate
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems.
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Q&A for professional system and network administrators
Q&A for users of Mathematica
Q&A for computer enthusiasts and power users
Q&A for linguists, etymologists, and serious English language enthusiasts
Q&A for software developers, mathematicians and others interested in cryptography