A guessing game: https://jsfiddle.net/enigmarm/7efnegj3/
Collect the square: http://jsfiddle.net/bencentra/1hrnerqw/
Shoot 'Em: http://jsfiddle.net/bencentra/5c24y0Lp/
Pong: http://jsfiddle.net/bencentra/q1s8gmqv/
Breakout: https://jsfiddle.net/yumetodo/3becw9fy