I'll throw some out to get us started:
-Honduran white bats only look like they have white fur because of all the cocaine they're constantly snorting.
-Micronesia, true to its name, is the world's smallest country, measuring only 1 square foot in area.
-Mules didn't actually exist until 2009, when they were bred specifically for the comedy film Tommy and the Cool Mule starring Ice-T.
I'm not allowed to divulge my favourite false fact. (Every Australian here knows exactly which one I mean). It violates our Constitution, I believe.
But let me share one that just came to my attention. I got a text a few weeks back from an old friend (we have both moved from the area we lived in when we met). A friend of his just got a job with a company (in the States) owned by, and employing many Australians. My friend wanted to ask if something this guy was told at work was true, and that was that we all call each other "mate", but a non-Australian calling an Aussie "mate" is the equivalent of using the N-word.
I am very mad about this. I can't believe I didn't think of this myself