ha!

I know it will make no difference to "skeptics", but an investigation in England chaired by Lord Oxburgh has found that "there was no scientific malpractice at the University of East Anglia's Climatic Research Unit, which was at the centre of the 'Climategate' affair."
Here's an idea: Do climate change skeptics think that there is no chance that the planet's getting warmer, and/or that the activities of mankind are behind it? If they think there's a chance, is it 1-in-2? 1-in-5? 1-in-10?
If you can get a number (let's use 1-in-10), ask them if they'd put a ten-chambered revolver with one random bullet in it to their head and pull the trigger? Or, more appropriately, their children's heads.
Unfortunately, rather than wake most "skeptics" up, this kind of analogy will simply make them deny that the planet is warming.