This is a list of puzzles, challenges, games, and other entertainment via coding. If you would like to see some added, please feel free to open an issue or (even better) submit a pull request on the GitHub repository.
NOTE: This list is in the public domain but I would appreciate a link back or at least a mention of where you got it if you repost it someplace.
- Codecademy (Interactively learn various programming languages working through examples and challenges)
- Code Kata (Routine exercises to keep chops sharp)
- /r/programmingchallenges
- /r/dailyprogrammer
- Stack Overflow list
- Advent of Code
- BTC Piñata
- Crack Me If You Can (password cracking)
- Cryptogeddon
- DesrevereDD0f
- Embedded Security
- Game of Hacks
- Gruyere
- Hack This Site
- Hacking-Labs
- HECF Sunday Funday Challenges
- Matasano Crypto Challenges
- Network Forensics Puzzle Contest
- Notpron
- OverTheWire Wargames
- Penetration Testing Practice Lab
- Pentester Lab
- Pwn Adventure
- Reverse Engineering Challenges
- RootMe
- SmashTheStack Wargaming
- Stack Exchange list
- Think Devise Hack
- Trythis0ne
- VulnHub
- XSS Challenge Wiki
- XSS Game
- Al Zimmerman's Programming Contests
- Annual Berkeley Programming Contest
- Code Chef
- Codeforces
- Codewars
- Croatian Open Competition in Informatics
- Eudyptula Challenge (Linux kernel challenge)
- Google Code Jam
- Hello World Open
- International Conference on Functional Programming Contest
- International Obfuscated C Code Contest
- International Olympiad in Informatics
- Internet Problem Solving Contest
- Kaggle
- Mystery Twister
- Programming Contests category on Wikipedia
- Project Euler
- Rosalind (Python and bioinformatics)
- Sphere Online Judge
- Tuenti Challenges
- uHunt (complement to UVa Online Judge)
- Beglitched
- CeeBot
- CheckiO
- CodeCombat
- CodinGame
- COLOBOT
- Command Line Murders
- Corewar
- Crobots
- Elevator Saga
- Exercism
- Git-game
- Grobots
- Hack 'n' Slash
- Infon Battle Arena
- Kodable
- Minecraft Hour of Code
- Mouse Run
- Problem of the Day
- Regex Crossword
- Robocode
- RoboZZle
- Scavenger Hunt
- SpaceChem
- TORCS Racing Board
- VIM Adventures
- CodeSignal
- Coding for Interviews
- HackerEarth
- HackerRank
- Interview Cake
- Leetcode
- Praetorian Tech Puzzles
- TopCoder
- 4Clojure
- CodingBat (Java and Python)
- Dyalog APL Competition
- Programming Praxis (Scheme)
- Prolog Problems
- Python Challenge
- Ruby Quiz
- Ruby Koans (The Ruby Path to Enlightenment)
- Untrusted (Javascript game)