The Oxford Comma & Ambiguity

Also known as the serial comma, the Oxford comma precedes the "and" or "or" before the last item in a list of three or more.  Its misuse can cause some humorous misunderstandings, as in the below example. 

[Tweet courtesy of @peterc.]

Unfortunately, adding the serial comma does not always clarify the ambiguity.  As wikipedia notes, "The Times once published an unintentionally humorous description of a Peter Ustinov documentary, noting that 'highlights of his global tour include encounters with Nelson Mandela, an 800-year-old demigod and a dildo collector.'  This would still be ambiguous if a serial comma were added, as Mandela could then be mistaken for a demigod, although he would be precluded from being a dildo collector."