Courtesy of commenter “Cornelius Breadbasket” at John Cook’s Skeptical Science:
100 climate deniers go into a bar.
Spencer goes up to the landlord and asks “do you sell pure alcohol?” “No mate, just the usual wines, beers and spirits” he replies. “Right lads, next pub” says Spencer.
The landlord is stunned. “What’s wrong?” he asks. “Nothing mate” replies Spencer, it’s just we require 100% proof”.
Of course, 100% proof is only 50% alcohol, but since when did that lot get anything right? :o)