Believe it or not, there was a Nintendo DS peripheral that allowed you to play your Nintendo DS on your TV.

As you can see, it works by sending the video/audio via component cables. It also meant that, by hooking it to a video/audio recording device, you would be able to record yourself playing a legit version of a game, without the means of the complex camera set-up deal. (Trust me. it's annoying trying to set that up for NDS.)
It was for a time sold on-line only, but eventually stopped for some unknown reason. However, I think I know why it never got mass-marketed. The guess is basically the demand being too high.
Think about it, the Nintendo DS is one of, if not the most, popular handhelds out there. The demand for such a device would be HUGE, and almost impossible to keep up with. I'm betting they just couldn't handle it and had to call it off.
Then again, it could be due to some legal issues we don't know about. Something that Nintendo just didn't agree upon for some reason. However, we'll never know, but I would've loved to get this when it did come out. If I had known it existed, I would've bought it immediately.
If I do find this being sold on-line, you'd bet I'd buy it, no matter how much it costs. (Even if I have to go into debt for it.) Until then, owning one is just a dream.
