My Very Own Mother Just Served Us Nine Pizzas.
True, Pluto's not a planet anymore, so we need to update that. But the bigger issue is that Earth does not start with the letter O. So I must be remembering it wrong.
I couldn't find anything definitive using Google - some said Earnest, some said Energetic, some said Educated, some said Eager, some said Excellent.
One even said she served us Pickles instead of Pizza. That one should be "My Very Evil Mother."
Anyway, so since Google let me down, I turned to my source-of-all-knowledge, and it did not disappoint. Check this oooouuuuut: Planetary mnemonic.
First thing you should notice is that I spelled mnemonic wrong. I guess I got it confused with mneumonia.
Anyway, the Wikigods say that it was Earnest until some losers changed it to Educated and took away the Pizza. I guess only us uneducated folks like to enjoy tasty cheesy goodness.
But now that there's no Pluto, it's all about Nachos:
My Very Educated Mother Just Served Us Nachos.
Hmm, education + cheesy food = not bad.