Girls are evil! Math shows that it is true!

[Zarora]

they invented... um... uh... the boomerang? Seriously, what else did an Australian invent?

Aboriginals invented the boomerang, they also were the first civilisation to use stone tools about 50,000 years ago.

Other things we've invented that I know of is:

Bionic ear
Clothes line - (The rotating kind. If you dont know what it is look it up.)
Spray on skin for Burns Patients - was developed/invented by Dr Fiona Wood and helped people who were victims of the Bali Bombings 2002.
Vegemite
Australian Rules Football - Very tough with no protective clothing.

And some I looked up :
Black Box Flight Recorder
Latex gloves
Xerox photocoping
Electronic Pacemaker