I was reading dmatt's weather forecast today. He mentions "a hint of moisture" and "on-going dry conditions". This made me think of the drought California is currently experiencing and made me wonder why people would want to ban dihydrogen monoxide as shown in the Penn & Teller YouTube. This YouTube will make you think twice before signing a petition again solicited by a girl or guy standing at the entrance of your local grocery store.
One of my favorites has always been: it's the main component of acid rain. You could also add that its the most abundant greenhouse gas. Try this one at home: when people finally figure out the dihydrogen monoxide joke, try it again with hydronium hydroxide.
