FormatExpress is an easy-to-use online formatter where you simply paste some bunch of raw XML, JSON, CSS or SQL, to get it automatically beautified. The most common use-case is to help reading minified input found in logs or web services.
A module for Prosody that implements a REST API. Meant for building bots. Can both accept and transmit XML and JSON. Can be configured to send replies to a callback URL. HTTP status codes 202 and 204 are interpreted as "message accepted" without needing to send an XMPP reply stanza.
GetSimple is a content management system that uses all flat files on the back-end - no database is required. It's fast to set up at pretty much any web hosting provider or on any web server. The user interface is clean and the undo function will let you revert nearly any change you make to the site. Even though the files are XML on the back end you interact with the site through a web browser, just like you'd update a site built using any other CMS. If you want to set up your first website this might be a good package to start with.
NWS Homepage of the National weather Service. Offers multiple kinds of weather forecast feeds - RSS and XML. API You can dig around to find the kind of weather data you're looking for; you'll probably have to go to the sub-sites linked
An online open and crowdsourced weather service. People set up automatic weather stations (which are fairly cheap) and contribute measurements that are aggregated into forecasts. Has an API so you can pull data out of it as well as contribute it: http://openweathermap.org/appid Free accounts are, of course, limited in several ways. You can also get weather maps of various kinds from the service to visualize the forecast data. Forecast data is in XML, JSON, and HTML formats.