Nintendo has declared the upcoming Halloween weekend another "National StreetPass" occasion, giving you a chance to mix it up with fellow 3DS owners from across the country from the comfort of your own town.
It will take place between October 31 and November 2, and like the first StreetPass Weekend, Nintendo Zone locations will be mixing up street passes from across the country. You can gather up to six from the hotspots at a time, which might help you catch a few states you don't have yet. It also suggests taking your 3DS out during Halloween weekend, presumably while trick-or-treating, to pick them up as you pass other ghouls and goblins.
The event will last between October 31 and November 2.