jRapidRPC is a Java RPC library that allows you to create client-server applications that talk in objects. It is small, fast, and extensible. Its smallness helps you learn how to use the library quickly. jRapidRPC is fast due to its compact size and lack of complexity. Also, it uses the ProtoStuff serializer by default. jRapidRPC's extensibility allows you to can write a new client-server or a new serializer.
Agnos is a cross-language, cross-platform, lightweight RPC framework with support for passing objects by value or by reference. Agnos is meant to allow programs written in different languages to easily interoperate, by providing the needed bindings (glue-code) and hiding all the details from the programmer. The project essentially serves the same purpose as existing technologies like SOAP, WSDL, CORBA, and others, but takes a minimalistic approach to the issue at hand. Unlike the aforementioned technologies, which tend to require integration with Web servers, using verbose XML-based protocols on top of textual transports (HTTP), often also requiring complex topologies (such as name servers for registering objects, etc.). Agnos is designed to be simple, efficient, and straightforward, allowing for direct communication between two ends using a compact binary protocol.
Beneath A Binary Sky is an engine that simulates a world in which robots controlled by programs can live, work, fight, and even bear new children. The long-term goal of the project is to create a fully configurable engine that can simulates any kind of world, from simple to complex ones with many rules and events.
nessus-xmlrpc is a Ruby library for the Nessus XML-RPC interface. You can use it to start, stop, pause, and resume scans. It lets you watch progress and status of scans, download reports, etc. It comes with an example command line program that shows how easy it is to interact with the Nessus scanner.