Fulworx is a REST framework that uses simple annotations of XWork "Action" implementations to expose restful interfaces. Similar to Struts, Fulworx sits as a controller on top of Restlet. Each action is attached as a resource using Restlets. Standard resources are represented by default as XML (or JSON) using JAXB, but any representation may be specified. Actions may be used in other frameworks such as Struts and Webwork, since they're just XWork implementations.
NanoHttpd is a lightweight HTTP server designed for embedding in other applications. It's only one Java file, in two "flavors", one strictly Java 1.1 compatible, and one at "current" standards. It supports GET, POST, PUT, HEAD and DELETE requests, and supports file uploading with very small memory overhead. Temp file usage and the threading model are easily customized.
PSX is a framework for developing dynamic Web sites in PHP. The goal of PSX is to help you develop RESTful APIs serving Web standard formats like JSON, XML, Atom, and RSS. It has a focus on social technologies and provides classes to use and implement OAuth, OpenID, Opengraph, Opensocial, Opensearch, PubSubHubbub, Atom, and RSS.