Famous stack overflow questions/answers:

• RegEx match open tags except XHTML self-contained tags, on parsing HTML with regular exprssions
• Why is this program erroneously rejected by three C++ compilers? on compiling C++ code
• Why is processing a sorted array faster than an unsorted array? on branch prediction
• What’s the toughest bug you ever found and fixed?
• What is the name of the “–>” operator?
• What’s your favorite “programmer” cartoon?
• The difference between covariance and contravariance

See also:

• Writing the perfect question