Or, Live Action Role Playing.
This came up over on Thee Missinglink's blog.
I know the world is kind of acronym heavy these days, but this one can be pretty useful.
You can easily use it to describe that part of our society that likes to play "Dress up" to escape the grind of an otherwise mundane life.
You know the types.
They're "Actors" in your local ren fair, Colonists rebelling against a King, people who make old fashioned facial hair work for them, crappy bands with an upright player that are somehow considered "Something-A-Billy" and of course, these guys:
They might sit in an office all week long but brother man, by the time that ol' weekend rolls around, they live to ride.