What do you call your grandparents? Confession added!!!

Having the bride at my families this year for christmas, she heard my sister referring to my Mothers Father as "Farvie"! To cut a long story short, it was started by my oldest sister when she was really little because she could say Gandfather. SHe also couldn't say Grandma, so she called her GRammy! They stuck with her and all my siblings. Yet my cousins all called them other names. Some Pa and Nanna, some pop and Gran and some Grandad and Grandma. So I was wondering what names some of you call your grandparents. Are there any unusual ones out there? 
