One example is Utility Mill. It is an application that lets you easily build Web utilities. These utilities have Web pages so you can interact with them. But they also have a RESTful API so they are actually Web services.
The utility can accept input in the form of parameters, process this input with arbitrarily complex logic written in Python, and output the results in several formats like text, HTML, XML, JSON or files.
Now, that’s a quick way to publish a Web service if I’ve ever seen one!