Implement OPTIONS method on all API endpoints
Whilst I was working on a project involving REST APIs, I came across this little article: http://zacstewart.com/2012/04/14/http-options-method.html
talking about the OPTIONS method for REST APIs. This method, documented in RFC 2616 section 9.2, "lets the client discover what it's allowed to do to a resource."
While this may not be terribly useful to everyone, it looked interesting and since it's a part of the spec, I figured it might be a quick little something to add to make the API even better.