Pull Request now includes Tetris!

completed: warmups
tower of Hanoi (with saving via YAML)
Mastermind(no saving, but yes AI)

Single block Tetris, with high scores saved, plus a difficulty setting as well. (Boring under about level 8).
Nice! At first I couldn't figure out where you were getting just the "player" from (I was expecting @player).  Great use of attr_accessor for it