Quadcopters

At a BBQ a few years ago one of the guests had a small quadcopter controlled by wi-fi from an iPad. Equipped  with stabilisers and an in-built camera it was able to fly over the assembled guests and we could all see ourselves on the iPad from about 20-30m above ground level. Prices then were around £200 but I expect prices have dropped. Great fun with iPad control and in-built camera. Of course drones have war uses, but this was a nice benign application. The design looked robust enough to survive the occasional crash although most have algorithms to land safely if out of wi-fi range, I believe.

See http://www.bbc.co.uk/news/technology-27403761 .