Nintendo 3DS Streetpass
Street Pass allows you to swap game data instantly with fellow 3DS players as you walk past them in the street. You won't need to stop and ask if someone has a 3DS or hold it at arm's length - as long as you have your console with you with the wireless on, as you pass people your fellow 3DS-ers you will swap data for supporting titles.
From other players' track times to beat in racing games, to inheriting fighting styles, rewards and other in-game items, there's plenty of opportunities to share with StreetPass. You can swap Miis and with other players and puzzle pieces, which, when completed, can be viewed in 3D. You can also take part in Street Quest where you use other peoples Miis to save your own from ghosts that have kidnapped your Mii.
Street Pass is fun and addictive and you'll always smile when you see the green light showing you have a Street Pass!