One of the best games I ever had was called Loony Labyrinth, which is saying a lot, because it's a pinball game. Now, I enjoy the occasional round of pinball, but I'm usually not too crazy about it. Loony Labyrinth, however, was an awesome game, just in the sense that you could never go far enough. Its coolest feature was the ability to "make the machine go back in time," by spelling out all the letters in Loony Labyrinth. When this happened, the machine kept its layout, but all the rules changed, meaning that in the end, as long as you were good enough, you got two games in one.
And I can safely say that if my computer would have installed it correctly, I'd still be playing it to this day, I enjoy(ed) it that much.