It's not a CTA "button" per say... but man, does it make you want to press down on it!
Blizzard's latest game, Diablo 3, has a beautiful button. Grab the PSD for this button here!
Great usage of interactivity with a sliding button
Creative way of showing a tangible version of a close button... but Cuberto is right, not so friendly to tear a photo up hehe
Great idea for a Chrome audio web experience