This is a list of puzzles, challenges, games, CTFs, and other entertainment via coding. It can include everything from ACM-style competitions to challenges designed to teach specific languages or programming paradigms. 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.
- CTF Time
- Codecademy (Interactively learn various programming languages working through examples and challenges)
- Code Kata (Routine exercises to keep chops sharp)
- Coders Dojo
- Pineapple challenges
- /r/programmingchallenges
- /r/dailyprogrammer
- Stack Overflow list
- We Chall
See the Trail of Bits CTF Field Guide and How to Get Started in CTF.
- Baidu CTF (in Chinese)
- BTC Piñata
- Codegate
- Cryptogeddon
- CTF365
- DC3 Cyber Crime Challenges
- Embedded Security
- Gruyere
- Hack This Site
- Hacking-Labs
- ISIS Lab CTF Challenges repository
- NICCS Cyber Competitions Repository
- Network Forensics Puzzle Contest
- Notpron
- OverTheWire Wargames
- p0wnlabs
- Penetration Testing Practice Lab
- Practice CTF List
- Pwn Adventure
- RootMe
- SmashTheStack Wargaming
- Sphere Online Judge
- Stack Exchange list
- ThreatSPACE
- Treasure Hunt
- XSS Challenge Wiki
- XSS Game
- Crackmes.de
- Crackmes.us
- DesrevereDD0f
- FLARE On Challenge
- NotPron
- Radare examples
- Think Devise Hack
- Tuts 4 You
- Bluehat Challenge
- Crack Me If You Can (password cracking)
- DFRWS Challenges (linked from individual years)
- Exploit Exercises
- Game of Hacks
- HECF Sunday Funday Challenges
- Insecure Programming by example
- Matasano Crypto Challenges
- Pentester Lab
- Skullspace
- Trythis0ne
- VulnHub
- A2 Online Judge
- Al Zimmerman's Programming Contests
- Annual Berkeley Programming Contest
- Cloudball
- Code Chef
- Codeforces
- Codewars
- Croatian Open Competition in Informatics
- Eudyptula Challenge (Linux kernel challenge)
- Google Code Jam
- HackerRank
- Hello World Open
- International Conference on Functional Programming Contest
- International Obfuscated C Code Contest
- International Olympiad in Informatics
- Internet Problem Solving Contest
- Kaggle
- Leada
- Mystery Twister
- Open Directory Project - Programming Contests
- Programming Contests category on Wikipedia
- Project Euler
- Rosalind (Python and bioinformatics)
- TopCoder
- Tuenti Challenges
- Underhanded C Contest
- UVa Online Judge
- uHunt (complement to UVa Online Judge)
- BerryBots
- CeeBot
- CheckiO
- CodeCombat
- CodinGame
- COLOBOT
- Command Line Murders
- Corewar
- Crobots
- Data Year
- DroidQuest
- Elevator Saga
- Exercism
- Git-game
- Glitchspace
- Grobots
- Hack 'n' Slash
- Infon Battle Arena
- Lightbot
- Kodable
- Mouse Run
- NessBots
- Problem of the Day
- Regex Crossword
- Robocode
- RoboZZle
- SpaceChem
- TORCS Racing Board
- Verigames
- VIM Adventures
- CodeEval
- Coding for Interviews
- Facebook Programming Challenge
- Leetcode
- Praetorian Tech Puzzles
- TopCoder
- 4Clojure
- C Puzzles
- CodingBat (Java and Python)
- Dyalog APL Competition
- Programming Praxis (Scheme)
- Prolog Problems
- Python Challenge
- Ruby Quiz
- Ruby Koans (The Ruby Path to Enlightenment)
- Rubeque
- Untrusted (Javascript game)