Google quietly updated their popular web-based RSS app Reader with a new fullscreen mode that hides all the clutter and navigation so you can focus exclusively on what you're reading.
You can toggle fullscreen mode on and off by hitting 'f' (as in fullscreen). When you turn on fullscreen, all the navigation, the search box, the external links, and all the rest of the space that isn't about reading your feeds vanishes, and all you're left with is the main content. To pull up the navigation or other buttons (like the always handy "Mark all as read"), you can hover your mouse over the very top of the window. Alternately, keyboard junkies can hit Shift+u to toggle the sidebar navigation, switch sources (Shift+j/k will move you up and down in the navigation sidebar), and open a subscription (Shift+o).
It's not a huge change, but if you spend a lot of time in Reader, it's a welcome one that cuts down on a lot of the default Google Reader clutter.