My friends call me Rei.  It comes from a mispronunciation of my first name.  It's spelled the Japanese way because I like the charecter Rei aka Sailor Mars (Ray-ana instead of Re-ana)  My dad calls me Nana Beth cuz when I was little I couldn't say Riana. A very few people call me Opie from my last name or Rio, from putting first and last together.  I think that's it...