Layer Tennis (née Photoshop Tennis) is coming back!  As summarized by Kottke:

Layer Tennis, the online Photoshop/Flash battle series, is gearing up for another season, starting on Feb 13th and running for twelve weeks. At the end of it all, there will be a single elimination championship tournament. Sign up for season tickets to keep informed and to be able to vote on the outcomes of matches.

In the meantime you can check out "volleys" from previous matches (e.g. this one).