Simrpc is a simple rpc implementation written in Ruby, relying on Apache QPID for the transport mechanism. I modeled it after Apache QMF, though nowhere near as complex (simrpc is procedural based for example, with data structures only encapsulating data, and not methods), intended to be a placeholder until QMF becomes a bit more stable.
I was able to whip it up pretty quick, it only took me a week to write end-to-end, and thus I'm releasing it under the MIT License instead of my usual favorite, the AGPL. Eventually its a possibility that I might rewrite it in C++ as there isn't anything ruby-specific in it and I could easily then after write a Ruby wrapper (or any other).
Have at it!