I have often wondered about the origin of the wooden spoon and it's association with 6 (and previously the 5 nations). After a bit of poking about on the web, the best I could come up with was that it was something to do with Cambridge University. However, I recently found the following article on Wikipedia which explains things quite well.
The wooden spoon at Cambridge, England was originally associated with the Cambridge University mathematical tripos exams, and was a kind of booby prize awarded by students to their fellow student ranked lowest in the final exams.
The custom dates back at least to the early 19th century, if not before, and continued until 1909. From 1910 onwards the results have been given in alphabetical rather than score order, and so it is now impossible to tell who has come last - unless there is only one person in the lowest class.
There were actual wooden spoons which became increasingly large, and in latter years measured up to 1.5 metres long. By tradition they were dangled in a teasing way from the upstairs balcony in the Senate House in front of the lowest-ranked recipient when he came before the Vice Chancellor to receive his degree.
The last wooden spoon was awarded to Cuthbert Lempriere Holthouse, an oarsman of the Lady Margaret Boat Club (http://www.srcf.ucam.org/lmbc/) of St. John's College, Cambridge in 1909 at the graduation ceremony in the University's Senate House. The handle is shaped like an oar and inscribed with an epigram in Greek which may be translated as follows:In Honours Mathematical
Or in more faithful prose: "This wooden object is the last souvenir of the competitive examinations in mathematics. Look upon it, and weep."
There was an equivalent prize for the last-placed classicist called the "wooden wedge", first won in 1824 by Hensleigh Wedgwood (1803-91) of the Wedgwood pottery family.
Nowadays the term, "wooden spoon", is used to denote the last-placed nation in the Rugby Union Six Nations Championship held every year between England, France, Ireland, Italy, Scotland and Wales (in alphabetical order). No physical wooden spoon exists or has ever existed in the case of rugby, however.
How the Cambridge wooden spoon idea came to be used in Rugby union is not exactly known, but in the early years of the Six Nations Championship there were many Cambridge graduates playing, so they may have attempted to preserve the concept after the last one was awarded in 1909. It is certain in any case that the tradition first arose in Cambridge and was later used by Rugby as a metaphor.