FlipFlop(2k)-this game is just like lights out. The object of this game is to turn all the circles to white. This can be done with as many moves as you like. When you turn a light on or off the surrounding four circles (up, down, left, and right) turn on or off depending on wether or not the light is on.
Mastermind(1.5k)- just like the board game. The calculator randomly picks 4 peices which can be any of the 6 different types. The object is to guess the pieces in the correct order. This isn't as difficult as it sounds because after each guess the game tells you how many pieces are in the corect space and another number tells you how many pieces are the correct type but not in the corrrect place.
Donkey Kong- I am working on this game now it should be done soon. This will have external levels and you can write your own.