The McCain campaign has put out a call on its website asking voters to "make an ad telling us why you are 'Joe the Plumber' in 30 seconds and your video could end up on the air as a TV ad." The call for entries can be seen here.
UPDATE (10/21): An Obama supporter named Baratunde cleverly posted this video so that it appears as the first Google search result for "Joe the Plumber Video Contest." The video leads viewers to Barack Obama's tax cut website.
"I am Joe the Plumber" by Baratunde: