In the deep south two boll weevils were born at the same time. One grew up and went to Hollywood, where he became rich and famous. The other one stayed on the cotton farm and became known as the lesser of two weevils.
A version of that weevil story was told in Master and Commander by the captain, played by Russell Crow. Supposedly, it was told to him by Lord Nelson.
I heard the koala joke from an Englishman who really used his accent and the Aussie imitation to full advantage.