Nintendo 3DS will let you go back to 2D
My eyes, my eyes

The 3DS - Nintendo's successor to the Nintendo DS that can purportedly spit out 3D images without the need for special glasses - will allow you to turn off the third dimension.
Nintendo President Satura Iwata "acknowledged people were already worried about the possible health effects of 3D gaming, such as on children's eyesight," writes the Associated Press.
"He promised it will be easy to turn off the 3D function on the new machine, allowing people to play games, with or without 3D."
The claim does make us question the level of innovation a game designer can bring to the 3D space, if the game must also work just as well once the third dimension is switched off.
We'll see in person once the 3DS debuts at this year's E3.
[Source: Associated Press]