This is somewhat off-topic, but I'm sure one of the PHP gurus can help.
I'm setting up an April Fool's joke on one of my sites. I need all visitors to be redirected to my April Fool's page UNLESS they've already been there. I will set a cookie once they land on my special page to track that they've already seen it.
I need to insert some PHP code into the Generic Header of my board to check for the cookie and redirect the visitor if it's NOT present. I don't know much about PHP, so any help would be greatly appreciated.