This one's a bit old, but somewhat amusing. Chris Mikaitis
alerted us to the story of an air conditioning company suing another air conditioning company for trademark infringement
over competing billboards. Apparently, the first air conditioning company came up with a billboard advertising campaign that read, in large letters:
"YOUR WIFE IS HOT -- BETTER GET YOUR A/C FIXED."
The competing company put up its own billboards, that read:
"YOUR WIFE IS NOT HOT! Because you called All Year Cooling to replace your A/C rather than the other guys."
This seems like a pretty amusing response. While the first company claims trademark infringement, suggesting confusion, it seems like perfectly reasonable competition. I'm reminded of a billboard that Informix put out a decade or so ago right in front of Oracle on the side of highway 101 in Silicon Valley reading "You just passed Oracle. So did we." It was amusing (if not particularly accurate), but as an advertising dig at a competitor, it seemed perfectly reasonable.