Wikimedia Foundation has announced that they are adding support for FeaturedFeeds extension on Wikipedia.
This means that you can now get an RSS/ATOM feed of featured articles and pictures on the various wikis operated under the Wikipedia network.
Wikimedia spoke about the update:
For now, links to the feeds only appear in page metadata; in the future, we will add them to the sidebar on main pages, if communities wish so.
FeaturedFeeds integrates with the existing main page infrastructure: it uses data from templates that show content depending on the current date.
Here are some feed links available from the Wikipedia English homepage:
Wikipedia featured articles feed: http://en.wikipedia.org/w/api.php?action=featuredfeed&feed=featured&feedformat=atom
Wikipedia "On this day…" feed: http://en.wikipedia.org/w/api.php?action=featuredfeed&feed=onthisday&feedformat=atom
Wikipedia picture of the day feed: http://en.wikipedia.org/w/api.php?action=featuredfeed&feed=potd&feedformat=atom