We've just bade farewell at work to a young woman, one of whose endearing qualities was the ability to engage her mouth before putting her brain into gear. Her bon mots were assiduously catalogued by one of her colleagues. The one I can remember that came closest to a malapropism was:

"Are you sure they're called tuxedos? Aren't they what the Germans used to bomb people with?"

Non-malapropisms included: "Do dogs have skin?" and "Tea comes from China - like polar bears."

The same colleague once explained her condition to her in this sympathetic way: "I've come across people before whose mouths work faster than their brains. But in your case, your mouth is doing 70mph the wrong way down the motorway, waving a whisky bottle out of the window, while your brain is still patting its pockets and muttering ' Now, car keys ...' "