Programming Praxis provides a collection of etudes, updated weekly, for the education and enjoyment of the savvy programmer.
Q&A for professional and enthusiast programmers
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
Q&A for people studying math at any level and professionals in related fields
Q&A for peer programmer code reviews
Q&A for professional programmers interested in conceptual questions about software development