I recently became aware of a web page that purports to show the difference between watering plants with water that has been heated in a microwave and water boiled by more traditional means. Supposedly, the plant that was fed the microwaved water died while the other did not. You can see that page here.
Naturally, I went to Snopes to see if they’d looked into it. They had and, as I expected, they considered the claim to be false. You can see their page about it here.
Why leave good enough alone, though? I’m going to try the experiment myself.