If you're into Game Boy nostalgia, the 3DS will include both Game Boy and Game Boy Color emulators with games downloadable from Nintendo's online store. No word on a Game Boy Advance emulator yet.
The company says it's planning interactive demos across the country with some 5,000 units available for customers to try the device out. Showing is of course Nintendo's biggest challenge with the 3D. You can't demo 3D gaming with static pictures or non-3D trailers after all.