National Coffee Day takes place on September 29, 2011. There are a few places that are offering free cups of coffee. I am sure there are more places participating so you might want to call your local coffee shops!
Krispy Kreme National Coffee Day Offer: FREE House Blend Coffee, 12 oz cup, with no purchase necessary.
Thorntons National Coffee Day Offer: FREE cups of coffee from 6 AM-2 PM.
7-Eleven National Coffee Day Offer: Participating stores will be giving away FREE medium cups of coffee.
Dunkin Donuts National Coffee Day Offer: There are press releases out saying coffee will be $0.50 a cup. I have not seen anything put out from Dunkin Donuts directly. I would call your local store and find out if they have a promotion.
Are there any locations not listed you have heard of participating?