But they'll cost you
In addition to a feature allowing users to back up their save data for downloadable 3DS games and most Virtual Console titles, Nintendo's newest 3DS firmware update has added premium StreetPass games. Look for all four of them available for purchase in the Mii Plaza as the update rolls out to different regions.
There's StreetPass Squad, a shmup from Good-Feel (Kirby's Epic Yarn); Ocarina of Time 3D developer Grezzo's StreetPass Garden; strategy title StreetPass Battle from Spike Chunsoft (Virtue's Last Reward); and Let's Tap studio Prope's haunted-house mystery StreetPass Mansion.
Shame Nintendo couldn't get this update pushed out before E3, as the expo was seemingly one giant excuse to get everyone to StreetPass one another.