Gettier walks into a bar and is immediately greeted with the assertion that all barroom furniture is soft, unless it's a table. So he produces a counterexample.
Comments are closed on the SSC link that gjm gave, so I'll post this one here:
Two baristas meet in the street, and burst out laughing.
Gettier walks up to the counter. Before he can order, the Barrista confuses him for a regular and chirps “I know what you want.” By coincidence, Gettier ends up with exactly the drink he desired. (from Alvin Goldman, Epistemologist Extraordinaire)