zeromq/netmq: A 100% native C# implementation of ZeroMQ for .NET was completely unknown to me (the C# version, not ZeroMQ), but it is a really exciting project for .NET enthusiasts. Directly in .NET without external libraries or even servers, you can build various 1:1, 1:N, N:1, N:M communication structures with diverse behaviors (Pub/Sub, Broadcast, Req/Resp, Fifo - basically everything that ZeroMQ can do). It makes a very good impression (ok, no surprise, it is after all an implementation of the original ZeroMQ in C#, and ZeroMQ was absolutely brilliant for its purposes). And of course, it is interoperable with the original ZeroMQ.