Wallabag is a “a self hostable application for saving web pages”. Basically, it’s a free, secure, and open source alternative to services like Instapaper, Pocket and Readability.
Beyond the Wallabag web interface, you can find Wallabag applications for iOS, Android and Windows Phone.
There’s also add-ons available for Firefox and Chrome, as well as a bookmarklet.
If you don’t have a server to run it on, you can use a free public server called Framabag. The Framabag website is mostly in French, but you just have to click on the button labeled “Créez votre compte / Create your account” to get started.