My grandmother on my dad's side:
"I'm gonna kill you and tell God you died."
"It's raining like a cow pissing on a flat rock."
My mom, after a good meal, will sometimes say, "Good stuff, Maynerd." To this day, I still have no idea who Maynerd is.
My grandpa on my mom's side, upon seeing a particularly "rough" looking man (tattoos, piercings, etc), would say, "Aiiiiinnn'ttt he puuuuurrrrdy!"