This past week I ran afoul of an interesting bug in Firefox 3 trying to serialize some stuff with fleegix.json.serialize.
Iterating over the properties of the DOMException (which for some inexplicable reason isn't an instance of a generic Error, but that's another rant) reveals the existence of a a
location property. But sadly, much like Nigel Tufnel's Fender Bass VI, this property is not to be touched, or even looked at -- if you actually attempt to access the property directly, you get the wonderfully intuitive error, "Permission denied to create wrapper for object of class UnnamedClass."
As it turns out, this bug has already been reported -- it's Firefox bug 436953.