I don't know if it was already posted, but apparently the DS is used in japanese McDonald's to train new employees. Here is a video:

Source

is there anything Nds can't do?

Uh oh. How will Burger King counter this?

DS, it only does EVERYTHING

Yes

PSP training?

I wonder if Nintendo actually built the game for McDonalds or if the Nintendo DS was just the platform ...

While this may sound a little silly, building software for corporate training would be a good way to build a small development team (and get them experience) on someone else’s dime. There would be other benefits of this too, most notably that the core focus of software like this would be much different than most videogames; and after completing the design and implementation of a couple of successful projects you would have a very different perspective on interactive entertainment than a conventional videogame developer would.

Now we need DS in the US education system...

Its what Miyamoto will do in japan ...

Yeah it even plays good games ^^ hahaha