Programming Puzzles & Code Golf Stack Exchange is a question and answer site for programming puzzle enthusiasts and code golfers. It’s 100% free, no registration required.

Here are the good parts:

• Anybody can ask a question.
• Anybody can answer.
• The best answers are voted up and rise to the top.

Checkout Area 51 on Stack Exchange. Area 51 is the Stack Exchange Network staging zone, where users come together to build new Q&A sites. New site ideas are proposed, discussed, and the best go on to beta.

Here are few awesome sites for programming puzzles:

• Programming Praxis
• Code Kata
• ACM International Collegiate Programming Contest
• IBM Ponder This(Puzzles provided
• for the purposes of evaluating potential hires)
• TopCoder
• Project Euler
• Facebook Engineering Puzzles
• Al Zimmermann’s Programming Contests
• Ruby Quiz
• Mind Cipher
• XOR Swap

Links:
Programming Puzzles & Code Golf Stack Exchange
Area 51 on Stack Exchange