Hotel Ginebra became the World's first business to accept ADA. When you visit their website, you will see immediately that they accept ADA, on the homepage itself.
They also have a detailed post on how the payment can be made and what the customer needs to know.
This is a good news for the Cardano community!
With Shelley being released in Q2 2018, which includes features like Debit card, I see more and more businesses can start accepting ADA