$10000 from Microsoft Australia if you use Internet Explorer 8 in treasure hunt.

My brother lives in Australia, so, if you find it, he will be very grateful and share the winnings with you.
Open only to Australians, Microsoft Australia hides $10000 that can only be found using Internet Explorer 8.
Here's the punchy ad copy they started out with (they have since toned it down)

source: internet explorer 8 treasure hunt microsoft-australia-hides-10000/