PsPong aka Photoshop Pong is a game
enjoyed by two (or more) players.
It's main object is an image.
Each turn, a player edits the image
a bit, or sometimes even radically,
making use of all the Photoshop skills
he or she got.
Over at the Asylum, a game usually
last's 8 turns.
Google query "photoshop pong" now returns asylum as the 1# result.