Is it a colour?
Depending on who you ask, black may or may not be a colour. A scientist will tell you black is the absence of all colours in terms of light mixing. But if you ask a painter then it is a colour because you can splodge it on a canvas, and you don't have colourless paint.
The phrase 'black sheep of the family' describes a member of a group who is undesirably different, with a rogue element implied. It dates back to biblical times when shepherds held the belief that a black-fleeced lamb was an unlucky omen. (Kudos to us for avoiding any of the usual, predictably suggestive comments about New Zealanders and sheep).
A black hole is a force in nature believed to be the result of huge stars collapsing under their own gravity. Nothing, including light or radiation, can escape one. More colloquially, a black hole is a place where money and objects vanish without trace. Sounds like the South Stand on Saturday or Sunday afternoon.
Supply, meet demand
The black market is free enterprise at it's rawest, the unregulated operation of supply and demand, which can be seen in the outrageous price mark-ups on Sevens tickets. Touting, both online and outside the stadium, can fetch three or four times the face value with 2006's HK$880 tickets going for HK$2,500.
Annals of marketing
Car magnate Henry Ford is reputed to have said about his Model T Ford: 'You can have any colour you like . . . so long as it's black.'