This has been mentioned in other Categories on this forum but thought it worthwhile posting for people who only read this section.
) is a site/browser plugin that allows you to archive web pages and save them to an account with a single click. So while your browsing or someone sends you a link and you don't have time to read, just click the button and archive it. You can then add Instapaper as a feed to Calibre and set it up so that every time you sync, it grabs your Instapaper feed.
P.S. it would be even better if Calibre didn't automatically set font-sizes on epubs it creates from news feeds as for now as we all know Kobo doesn't handle that well.