My activity log says:
122:42 - Streetpass Mii-Lobby (I think that is Streetpass-Plaza in english)
114:59 - Kid Icarus: Uprising
113:06 - Fire Emblem: Awakening
98:32 - Resident Evil: Revelations
As I said, Streetpass is the ingenious new feature of the 3DS, not 3D. And you can see the Top 3 of my played games.