An aerial, unmanned books delivery service might soon start in Australia. Flirtey, a tech statup born in Sidney University might well extend the plan to delivery of other good such as food and drink in the future.
The Flirtey website states that they are building an industry, not a company. At such an early stage of this technology, with so many still unexplored potential applications this might well be true.
Similar services are also under experimentation in the US, where Dominos plans to deliver pizza by a special multirotor called, you guessed it, the domicopter. However this one might be more an advertisement move that something that will really happen (in a near future). Here you go with unmanned pizza delivery from Dominos: