The lucky bods at IGN have got their hands on the DS' first "Option Pak". It wasn't all good however...

First off, the basics. The DS Rumble Pak looks exactly like a GBA cartridge, and fits snugly into the GBA slot on your DS. On the DS main menu, it will tell you an "Option Pak" is inserted where the "Start GBA game" message usually shows up.

The first game to support it is Metroid Prime Pinball, which tells the special innerworkings of the cartridge to vibrate when you whack into obstacles, vibrating the whole DS as well. No other games support it - having it in your DS while playing any other game won't make it spring to life! Unsuprisingly, placing the Rumble Pak in a normal GBA and turning it on doesn't bring forth any magical rumbles either.

IGN weren't all that happy with their Rumble Pak, saying their's was "one of the noisiest Rumble Paks Nintendo has ever built." They claimed that while playing Metroid Prime Pinball, they could hear the rumble mechanism more than actually feel its rumble effects, leading them to suspect the Pak they were sent was possibly broken!

Fortunately, they report the actual game was far better than the dodgy Rumble Pak. Take a look at the Pak on IGN's page here (it just looks like a GBA cart).