I wouldn't normally think a library is LtU material, but since this one lives at the intersection of embedded DSLs, process calculi, and a spotlight language, I think it fits: Communicating Scala Objects , Bernard Sufrin, Communicating Process Architectures 2008.

In this paper we introduce the core features of CSO (Communicating Scala Objects) – a notationally convenient embedding of the essence of occam in a modern, generically typed, object-oriented programming language that is compiled to Java Virtual Machine...