If your organization is looking to create a new OOH campaign to sell season tickets, consider creating billboards that say, "Looking for a Sign to Buy Season Tickets This Year? Here it Is". Organizations can take this call-to-action to the next level by accompanying it with a special promotional offer (discount on tickets, free premium item giveaway, unique experience, etc.).
Just remember - if you go ahead and use this idea... just remember to tell people where you found it!