I wrote a GUI version of Game of Life in C++ using the SDL2 graphics library:

https://github.com/gdonald/game-of-life-cpp

I wrote a GUI version of PigPen in C++ using the SDL2 graphics library:

https://github.com/gdonald/pigpen-cpp

I wrote a GUI version of TicTacToe in C++ using the SDL2 graphics library:

https://github.com/gdonald/tictactoe-cpp

I wrote a Console version of Blackjack in Ruby.