This might be the Link of the Month: The Superest. Artists Kevin Cornell and Matthew Sutter compete in a continually running game of My Team, Your Team. The rules are simple: Player 1 draws a character with a power. Player 2 then draws a character whose power cancels the power of that previous character. Repeat. Not only are the strip ideas mighty clever, the site itself is very nicely designed.
Update
A little background from Cornell, based on an idea from here.
See also: Layer Tennis.