I graduated highschool in 2010. During my time at highschool we had more and more trailers, but by the end of it (and maybe before that) we had as many rooms outside as we did inside.

I have a strange nostalgia for them. I live in the southeast US, so it's really hot. The AC on these things was crazy. You basically had to wear jeans and a hoodie year round because you'd get too cold otherwise.