I'm embedding Wikipedia pages in my app, and I'd like to show the same simplified abstract that Google Earth shows. (It gives the first several paragraphs and a link to the full content, without any serious layout.)
I know about the printable=true option, but that's not what I'm looking for.
You might want to consider using the API : you can grab a "text" version of any article. Afterwards, it is up to you to extract the summary.
Another option is just to request the page in raw format:
Raw (Wikitext) page processing: sending a action=raw or a action=raw&templates=expand GET request to index.php will give the unprocessed wikitext source code of a page.
E.g.
http://en.wikipedia.org/wiki/Main_Page?action=raw
Of course you'll need to do a bit a scraping. Going through the API might prove more efficient as you have better control of what you can pull from the database directly (wikitext if you wish).
Did you look at the Wikipedia API? Mediawiki (and so Wikipedia) has a feature-rich and flexible API which is documented on http://www.mediawiki.org/wiki/API
Use the mediawiki API with action=query and prop=revisions to fetch a given revision , remove the wikitext ( images, infoboxes) and extract the content of the first sentence.