While not a game per se, I found Mitoza intriguing enough to spend quite some time with it. You start off with a seed, and are then presented with two choices: you can either click a flower pot, or click a cute little birdie.
If you click the flower pot, a flower pot appears and the seed is planted inside. You’re then presented with two further choices — a water can or a bottle of fertilizer. Each choice you make causes your creation to morph, and presents you with two other choices.
There’s no winning or losing, really. Each “game” usually lasts around four or five choices, at which point the plant/animal dies in some creative (but not too gruesome) way. At this point you instantly start over with a new seed.
The graphics are captivating; the whole thing has a cinematic feel to it, with a bit of artificial camera shake added for style.
All in all, it’s a fun, peaceful way to spend a few minutes, and it might even make you think a little bit while you’re at it.