Code Golf: Print the entire “12 Days of Christmas” song in the fewest lines of code

Answer 1

Linq to objects, in 580 characters (without whitespace)

Console.WriteLine(Enumerable.Range(1, 13).SelectMany(day =>
    Enumerable.Repeat("\nOn the " + day + 
                      (day == 1 ? "st" : 
                      (day == 2 ? "nd" : 
                      (day == 3 ? "rd" : 
                      "th"))) + " day of Christmas my true love gave to me ", 1)
              .Concat((new []
                {
                    "twelve drummers drumming,",
                    "eleven pipers piping,",
                    "ten lords a-leaping,",
                    "nine ladies dancing,",
                    "eight maids a-milking,",
                    "seven swans a-swimming,",
                    "six geese a-laying,",
                    "five gold rings,",
                    "four calling birds,",
                    "three french hens,",
                    "two turtle doves, and",
                    "a partridge in a pear tree."
                }).Reverse().Take(day).Reverse()))
              .Aggregate((a, b) => a + "\n" + b));