Hessian
From Resin 3.0
The Hessian binary web service protocol makes web services usable without
requiring a large framework, and without learning yet another alphabet
soup of protocols. Because it is a binary protocol, it is well-suited
to sending binary data without any need to extend the protocol
with attachments.
Hessian Downloads
See http://www.caucho.com/hessian for the current downloadable versions.
Language Implementations
.NET C#
C# implementation of Hessian is available at http://www.hessiansharp.org under the GPL at Sourceforge by Dimitri Minich, Vit\ aliy Byelyenkiy and André Voltmann. Hessian - C# Implementation