Oh I just remembered one...these aren't really weird spellings so much as just "different" names, but still...

My aunt's name is Voniessa (pronounced Vuh-nee-sa)....but when they were little, she wound up with the nickname "Neccar"...people always look at us funny when we refer to her as that (well, people who don't know her nickname, anyway). Apparently her siblings had a hard time pronouncing her real name when they were kids, and it got shortened to "Neesa" then somehow to Neccar....and it just stuck.

My grandpa's name is Verlin, which is unusual now, but I suppose "back in the day" it was a more common name.