Flipboard CSS buttons
Flipboard creates a series of CSS buttons that flip horizontally on themselves when the mouse rolls over them, creating an elegant, eye catching effect. It employs CSS3 transform and transitions to do the heavy work.

Image frames using CSS3 border-image
CSS3 makes it possible to specify an image as an element's border, instead of just a solid color. It takes a single image and then slices and dices it before using the end pieces to make up the border. Very cool!

Image with sliding description panel using CSS3 transitions
This CSS example shows how to add an animated description panel to images that slides open when the mouse rolls over the image using CSS3 transitions.

Pull out image using CSS3 keyframe animation
CSS3 animation can be fine tuned and broken up into "frames", thanks to the @keyframes rule. Currently supported in FF5+, Safari, Chome, and possibly IE10, the following uses CSS3 keyframes to create a pull out image that is revealed when the mouse rolls over an image. In IE, it degrades well in both IE8 and IE9.

Pure CSS3 Push Down Panel
This is a CSS3 push down panel that when clicked on reveals some content, pushing the rest of the page's content down in the process. The entire interface is created using CSS only, using a combination of CSS3 shadows, round borders, and CSS2 generated content.

Rollover Text Menu
This CSS menu creates the popular rollover text effect of text sliding up to reveal a duplicate of itself when the mouse rolls over a menu item.

Spinning icons using CSS3 transform
An effect that seems to be popping up with increased frequency is the spinning image, or more precisely, icons. Move the mouse over an icon, and it spins (rotates) on its axis to draw attention to itself. This is realized using CSS3's transform: rotate(xdeg) property.