On the day, you can dress as a cow and score a free meal at any Chick-fil-A nationwide.
To get that free meal, which includes an entree, side item, and drink, you'll need to be dressed "head to hoof" to somewhat resemble a
cow (trotting around on all fours is not required but might provide some entertainment value). If you don't wish to go "full cow," you can still get a free entree by being "partially dressed in cow attire," which can be as simple as a cow-spotted tie, hat, or purse.
If you're not quite gung-ho enough to buy/make your own costume, Chick-fil-A has a do-it-yourself printable costume available on their Tumblr page here.