When Nintendo first unveiled the DS, they made a lot of hoo-hah about it having a microphone - despite the fact that the only thing any of the early games did was to let you blow into it to snuff out candles or inflate balloons.
Fast forward three years, and what are you doing in Zelda: Phantom Hourglass with that cutting-edge microphone function? Yes, you're blowing into it to make windmills go round and fires go out – interspersed with one exciting moment where you shout to get someone's attention. The new frontier of game controls, this ain't.
Plug and chat
That said, Nintendo's voice headset is good at what it does - plug it into the headphone socket of a DS or DS Lite, and it replaces headphone and mic for voice chat or voice commands.
It's solid, works without glitches, and has noticeably better sound quality that listening via built-in speakers. To chat to other players, you need to have their friend code, but it's pretty problem-free, and doesn't lag out even if you're playing across a not-brilliant Wi-Fi connection.
So what can you use it with?
Sadly, games to use it with are thin on the ground. Pokemon, Metroid Prime Hunters… but a lot of other big-hitting multiplayer games on DS, such as Mario Kart, don't have the function built in. This isn't like the 360 headset where it'll work across all your games - not by a long shot.
With Brain Age, the mic does work pretty smoothly - but the improved sound quality seems to have no impact on our DS Lite's inability to hear us say the word 'blue' in that colour-match game that always knocks our age up a couple of decades.