In an Politico article about Barack Obama's vice presidential choice, Joe Biden, the Delaware senator is described as someone who "can also deliver stemwinder." I'd heard this word only once before, about a year ago at work. In this use, it means "a rousing speech," according to Webster's New World.
That's the second definition, though. The first definition is the second's origin, "a stem-winding watch." Though a good stemwinder (the speech, not the watch) can go on for a long time, the adoption of term for public speaking has nothing to do with the need to wind your watch while listening to it. As Slate explained in a 2004 article:
The term dates back to the middle of the 19th century, when the stem-winding watch came into vogue. The newfangled timepiece was a vast improvement over its predecessor, the key-wound watch, because the mechanism for setting it was a stem actually attached to the watch, rather than a key that was easily and frequently misplaced. This technological advance was so widely appreciated that, by the end of the 1800s, the term stemwinder had taken on the figurative meaning of "excellent" or "outstanding," or, as the Oxford English Dictionary puts it, "a person or thing that is first rate."
It's the 19th century's version of "better than sliced bread." Of course, that's outdated too.