Timer
Create a useful tool for toothbrushing, cooking, and more!
Cellular Automaton
A fun way to create interesting patterns based on simple rules.
Hangman (or Snowman)
Put your own spin on this classic word game.
Number Pyramid
Write a program to display a symmetrical pyramid of numbers.
Dice Roller
Need to roll some dice? Write a program for that!
Tower of Hanoi
Code a solver for this famous puzzle using recursion.
Flappy Bird
This popular game is always a fun time. Put your own spin on it!
Binary Birthday Game
Guess a person's birthday using only 5 binary bits.
Caesar Cipher
Create encrypted messages using this simple cipher.
Coin Toss
Need to flip a coin? Write a program for that!
Palindrome checker
Enjoy word puzzles? This one might be fun for you!
Number Guessing Game
Play this simple game against a friend or the computer.
Snake
Create your own version of this popular game.
Yoda Speak
Translate plain old English into Yoda's way of speaking.
VIM Adventures
An online game for learning how to use the vim text editor.
Insertion Sort
Sharpen your skills by coding this simple sorting algorithm.
Fibonacci Sequence
This simple number sequence has a lot to offer coders, from simple iteration to recursion and dynamic programming.
CSS Diner
Learn and practice CSS selectors in an interactive game.
Pong
Create your own version of this popular game.
OverTheWire Wargames
Learn and practice hacking/security concepts in the form of fun-filled games.
Joke Bot
Have some good jokes? Make a bot to tell them! Or, get some jokes from an API.
Calculator
Create a basic or advanced calculator.
Tic-Tac-Toe
Here is a shorter description.
SQL Murder Mystery
Can you find out whodunnit?
md5 cracker
Write a program to decrypt this common hashing algorithm.
Unit Converter
Create a handy tool for converting temperature, weight, time, or distance.
Bubble Sort
Sharpen your skills by coding this simple sorting algorithm.
Chinese Zodiac Calendar
Display each animal sign and tell people which sign they are.
Screeps
MMO sandbox game for programmers
Regex Crossword
A crossword puzzle game, where the crossword clues are defined using regular expressions.
Sudoku Solver
Write a program to solve Sudoku puzzles.