A cool image gallery implemented purely in CSS. The images pop out when you hover over them. There is no Javascript used in this at all.
Link: Hoverbox Image Gallery

If you’d like to know how this is done, you can go through a mini-tutorial over here:

http://sonspring.com/journal/hoverbox-image-gallery 

Here’s another example of the same CSS method being used to create a menu system:

Link: Hoverbox Menu