Free Milkshake at Johnny Rockets 9/9 0 comments September 9, 2013 Birthday Freebies Free September is National Shake Month! Johnny Rockets is celebrating on Sept. 9. When you are grabbing that delicious lunch, be sure you tell your server the secret word, “Yummy” and you will receive a Free Milkshake! Delish! Follow Me on Social MediaEnter your name and email for free coupons and offers! Sign Up Now!