So, if you toss an American quarter in Australia, does it drop clockwise or counter clockwise?
Yes, it does.
Are you dissing our Zombie Jefferson nickels?
When I was in the Sydney airport, flying back to the U.S., I went ahead and exchanged my money. The cashier counted out $10 in $2 bills and handed them to me. I hadn’t seen a $2 bill since I was a little kid.
Actually, take a look at this video of George.
Those poor United Empire Loyalists!
Very sadly, 25 months later, that coin is now worth about 25 cents in Australian money: the AUD and USD are trading at close to par now.
I think this is a consequence of the quarter, dime, and 50 cent piece being originally silver coins, so the sizes were proportional (2.5 dimes weigh one quarter; two quarters weigh as much as 50c, four quarters weigh as much as an old silver dollar).
The Australian 10 cents and 20 cents coins are descended from silver coins too: the British shilling and florin coins, which were the same size as the current Australian coins. (In the U.K. they reduced the sizes of their descendants, the 5p and 10p coins.)
Our quarter could kick the shit out of your 20¢.
Isn’t that Austria? 
It will be fun to compare when you get coins from Guilder and Florin.
shhh – Green Bean declared war on Australia in post #4, and probably spent the last 2 years looking for it between Germany and Italy.
It explains a few of my favorite things.
My husband once got a swiss franc as change from a soda machine. It should have been a nickel, so that was a big upgrade. The great thing was we were going to Switzerland so we could actually use it.
I’ve received Canadian change in the US as well as US change in Canada. The coins below $1 are basically the same sizes and colors, and people basically don’t seem to care a whole lot about a single coin in change from the other country.
Gotcha. 
My dad used to go to Asia for business trips, which is probably why I’ve found the odd coin from Taiwan or the Philippines lying around. Also some Israeli agorot and shekalim, but we’ve been there several times.
My dad’s prized foreign money is from Zimbabwe. When we were safari-ing in Africa, he got into a discussion about the laughable inflation with a nice hotel clerk, and the clerk gave him a souvenir five million dollar bill. Worth, oh, slightly less than the paper it’s printed on.
Never seen any Australian currency, though.
Getting American coins in your change is quite common up here. But no place will exchange coins for their correct and current value–only bills can be exchanged. So, in Canada anyway, nobody really cares–a quarter is a quarter, US or Canadian; and as a result, American coins tend to circulate at par value with Canadian coins.
…and they did so even before the currencies were at par (ish).