Samorost! This is by far the greatest Flash game ever. It's beautiful and a lot of fun to play. It's a point and click puzzle game. Figure out the sequence and objects in each screen to move on to the next screen. My four year old loves this. It's like an interactive picture book for him. I'm crazy about the artwork and feel of it.
When you finish the first game (it's not a long game), try the sequel (the link is at the top of the page).
Happy gaming and enjoy the eye candy and the super cool music and sounds.