Just go the Ahh Giver Page on Facebook and you can send a friend a FREE 20 oz. Coke!
Just choose one of your friends, write a message and send it. Your message will be posted to your friend's wall. Once they watch the message, they can print their coupon valid for 1 free Coke.
The page doesn't say how many coupons they're giving away or whether there's an expiration date on this deal, but it does say they re-stock on Mondays, so if it doesn't work today, try again.
Thanks to Mrs. Moneysaver for this tip.