It's a shame there isn't some simple standard (de-facto or otherwise) way of documenting REST APIs such that an idiomatic client library for each language could be generated automatically.
Check out github.com/RestDoc/specification, it's a project that got started after a few people (myself and Zac included) realized we were all solving the same problem. It's been languishing in relative obscurity because most of us don't have the bandwidth to properly promote it, but more contributions are very welcome!
The OPTIONS method is a really underused part of HTTP and would be great for this purpose: http://zacstewart.com/2012/04/14/http-options-method.html