"Bart vs. Australia" is the sixteenth episode of Season 6.
The episode begins with a bathroom products race between Bart and Lisa in the bathroom sink. Lisa wins and Bart suggests she won because her shampoo was in the "inner lane" to his toothpaste. Lisa explains the Coriolis Effect to Bart (not entirely correctly), but he does not believe her. He makes a collect call to an Australian boy, and asks him about which way the water drains. The line is kept open for several hours. When Bart does not hang up, the Australian boy's father is billed $900. The man wants Bart to pay, but Bart mocks him. Bart receives dozens of collection letters in the mail, but does nothing about them.
Eventually, Australia indicts Bart for fraud. The United States State Department wants to send him to prison, but settles upon having Bart personally apologize in Australia. The family is sent to Australia, where they start exploring the culture. Bart makes his apology, but they want to give the additional punishment of a boot to his buttocks (a parody of the Michael P. Fay caning incident in Singapore). Bart and Homer escape the booting and they try to run back to the embassy. Bart agrees to have them do the booting anyway, but as he is about to receive his punishment, he moons the Australians. The Simpson family leaves the outraged country in a helicopter in a scene similar to the Fall of Saigon. A subplot through the episode where Bart brought his pet frog into the country past customs, where it reproduces and spreads rapidly throughout the country and ruins Australia's ecology (a reference to the actual introduction of non-native Cane Toads into Australia). As the family is being flown home they happily remark upon the destruction that can be caused by introducing a foreign species into a new environment...as the camera pans out to reveal a koala hanging from one of the helicopter's struts.
Behind the Laughter
This episode marks the first time the family has visited another country.
In Australia, the episode was met with criticism due to its hugely inaccurate and stereotypical portrayal of the country, although it has been accepted as typical American satire and is still aired as a re-run as often as all other episodes. Some Australian fans of the series rather consider it an honor that Australia was featured so much in an episode at all. Subsequent Simpsons episodes exploited existing stereotypes of other countries, but this episode actually fabricated things about Australia wholesale, as the Simpsons producers admit in the DVD commentary for this episode.