Live-action role-playing (or LARPing) was born on the fringes of American pop culture, a descendant of much-maligned hobbies like Dungeons and Dragons and other table games.

In LARPing, players spend their weekend dressing up in costumes, adopting elaborate personae, and inhabiting a complex imagined world.

The hobby, like most of "nerd" culture, has become increasingly mainstream.

Across the US, Canada, and Europe, LARPing groups are everywhere. There are more than 30 LARPing organizations in the US, each of which has tens of chapters and thousands of members.

A few weeks ago, we visited Alliance, one of the oldest live-action-role-playing groups in the country, in central Pennsylvania, to figure out what LARPing is all about.