ds
Nintendo's successor to the Game Boy line of portable game players. Originally marketed as a "gameboy for the older age", it offers a novel feature of having two screens, the lower of which is a touch screen used to interface with certain games. While it's hardware is certainly superior to Nintendo's previous systems, it has often been criticized of being overly limited as only a game player. A small cartidge allowing the use of mp3 files to be played was supposed to have been released. It has a WEP capable wireless ethernet card, and McDonalds is running a promotion offering free wireless for DS owners. Heavily paraded games include: Super Mario 64 DS, Metroid Prime Hunters, Nintendogs, Elite Beat Agents, and others.
 

Succinctly put:
Dual Screens.
Touch screen.
'Different' games.
Microphone.
Rudimentary wireless internet.
Relatively inexpensive.
The DS is a portable entertainment device. I have one, but I find it rather gimmicky. Props to Nintendo for thinking of it though. 