Tranquility

Tranquility is a FireFox extension that improves the readability of web articles.

Tranquility removes unnecessary elements in a webpage, and provides a simple and tranquil reading experience. Similar functionality is available through Readability or iReader. Tranquility attempts to solve the same problem using a different approach.

To use tranquility you can:

Click on the navigation-bar icon and the current web-page will be made readable OR
Use Ctrl+Alt+T as a keyboard shortcut OR
Right click on a link and choose "Tranquility!" from the context menu. A new tab will open the link in the Tranquility mode.
Heavy users of Tranquility can enable the Pause/Break button as a single key shortcut
Macintosh users are requested to use the Customizable Shortcuts addon to create their own customized keyboard shortcut

The navigation-bar button or the keyboard shortcut can be used to toggle back to the original web page. A drop down menu attached to the navigation-bar button provides easy access to the preferences window.

Features:

Compatible with NoScript
Ability to customize default font, font-size, font color, background color, and width of the reading area
Preliminary support for multi-page documents (where a print view or a single page view is provided)
Selected text can be queried in Wikipedia or Wiktionary through right click context menu options or using the keyboard shortcuts Ctrl+Alt+W and Ctrl+Alt+D respectively. Click outside the Wiki panel to hide it
Ability to disable the background image from the preferences window
Additional links are now available through a "More Links" button
Tranquil Browsing Mode is enabled by default. In this mode, left clicking on a link in the Tranquility view will also open the link URL in the Tranquility view in the current tab. Ctrl+Left Click will open the link URL in the Tranquility view in a new tab
If a web page has not completed loading fully, Tranquility will wait for it to complete loading before processing the document
Tranquility informs you when a web page has very little text content and reverts back to the original web page view. You can always force Tranquility to proceed anyway and show you the Tranquility view

Release notes: http://tranquility.ushnisha.com/tranquility_release_notes.html