World of Goo is a nice ride.
Plants vs Zombies -> was mentioned, but I mention it again.
so much fun, end song is a killer
Child of light -> if you are not a completionist and don't want every stone (quest) unturned is a nice ride. You will have to think though, not a hack'n slash
Solar 2 -> small, easy to play...once you become a black hole, that is
Prince of Persia 2008 - the cell-shaded one, once you get the hang of the quick-time events
Trine -series- colorful and bright and cheery
Abzu - kind of artsy game, pretty graphics, but not sure I like it
Beyond blue - swimming around with actual sea animal, even educational
Flower - you are.....the "wind" and you have to help plants