Wikipedia
JoCaml
JoCaml is an experimental functional programming language derived from OCaml. It integrates the primitives of the join-calculus to enable flexible, type-checked concurrent and distributed programming. The current version of JoCaml is a re-implementation of the now unmaintained JoCaml made by Fabrice Le Fessant, featuring an modified syntax and improved OCalm compatibility compared to the original.
JoCalm was used by team Camls 'R Us to implement a distributed ray tracer, earning 2nd place on the ICFP 2000 programming contest.