Here's another possibly obscure one! This story was published in two or three parts in issues of Cricket magazine in the early 2000s. I'm not sure if it was written for the magazine itself or was part of a larger story and adapted for magazine format.
The story involves two cultures floating aboard a spacecraft after, ostensibly, the destruction of Earth. The two cultures exist separately on two different side of the ship and are unaware of the other's presence until the main character accidentally discovers the other culture. The name of the ship is the Boreas.