2048
When this game became REALLY popular, I decided I must make my own version of it as well - just to see how fast I can code the game using my current knowledge - without looking up the source code for the original 2048 game. I coded the entire base game (minus beautiful graphics) in roughly 2 hours on a bus ride from San Antonio to Houston. This was really a fun project for me so I added many "cheats" to the original base game, making it my own: