Microsoft unveiled the box art for the upcoming Halo 4 game by emailing Xbox community members one of the 32 pieces of puzzle that when assembled together reveal the image. The puzzle was cracked in about an hour, probably helped by the fact that the remaining 31 pieces could be seen by changing the last two digits of the image URL before the ".jpg" part, a fact that wasn't lost on the fans:
http://image.engage.xbox.com/lib/feca167070610c7c/m/4/12993-H4_02.jpg