Yesterday, 10 free NES Virtual Console games were dispensed to 3DS owners who had purchased the hardware before the price cut. And it looks like those gamers won't be playing their VC games alone.
Pointed out by Kotaku reader Siegling, it appears you can switch from one player to two player controls, which would appear to mean that local multiplayer is possible. I haven't have the chance to try this with another 3DS owner, but I could easily switch between one player and two player controls.
Watch the video to see how I did it.
(And no, I do not have three hands. But I did get temporary tripod help -- thanks Mrs Bashcraft!)