Go to Australia and you will probably see restaurants that say B.Y.O on the menu or on a sign somewhere on the front of the shop. What does it mean?
Well, in Australia liquor (alcohol) licenses are limited and very expensive, so it is often impossible for some restaurants to get one. Customers are however free to bring there own booze (normally beer or wine). And that's what B.Y.O stands for, Bring Your Own. If you notice a restaurant has a BYO sign and you feel like a drink with your meal, you will need to pop down to the nearest bottle shop (liquor store), most likely the closest pub, and grab some drinks yourself.
Some places may charge a small corkage fee (this is a few dollars charge for opening the bottle and is a bit annoying) and be careful not to take drinks into an establishment that does have a license, that's a no no.