Originally Posted by ski

Friend had it in his profile:

Why do golf courses have 18 holes - not 20, or 10, or an even dozen? During a discussion among the club's membership board at St. Andrews in 1858 a senior member pointed out that it takes exactly 18 shots to polish off a fifth of Scotch. By limiting himself to only one shot of Scotch per hole, the Scot figured a round of golf was finished when the Scotch ran out.