Recently I have started to notice a trend on new websites for them to have 'cut-outs' revealing parts of an image below the 'content'. Apple do this in sections of the site on their iPhone webpage, however it's clearer to see on this eBay mini-site: http://pages.ebay.com/announcements/new/index.html
What I am wanting to know is either how it could be achieved using HTML, Javascript, CSS etc.. or even just the name of the script design (like image sliders are called 'carousels' etc). Done a couple of searches online, but all to no avail....so I ask you, people of Metropol, any ideas?

Thanks,
-James