Recently we announced that Mono achieved full C# 3 support. Along with that comes support for Parallel LINQ. Parallel LINQ, part of Microsoft’s Parallel Extensions library, allows developers to quickly make queries execute across multiple threads.
Jeremie Laval was able to take “Luke Hoban's brutal ray tracer-in-one-LINQ statement program” and parallelize it with only minor changes such as replacing “Enumerable.Range” with “ParallelEnumerable.Range”. You can read more about PLINQ on Mono Miguel de Icaza's web log.