gray in the US
grey in the rest of the English speaking world.
"Grey", "gray"...what's the difference?
You "rest of the English" speaking world also spell flavor/color/honor with a "u"...what's up with that, eh? 
I actually have fun searching for misspelled words...especially since my college courses have been going on for a while. We just had a lesson on the "most common" misspelled words. Ya know, there is a dang lot of them!
To be honest, I've actually copied and paste posts from spelling critics here on JWD to see if they have misspelled words, and yep, there has been...not as many and not as noticeable.
Not only misspelled words but there are a lot of fragmented sentences from these "critics", so fun to see.