Get out your pens and paper for the world’s quickest #history lesson on the #ShamrockShake, courtesy of McDonald’s Archivist Mike Bullington and his besties, Grimace and Uncle O’Grimacey 📚☘️ Your favorite green treat is even sweeter this year – from February 10 – March 23 at participating U.S. #McDonalds restaurants, 25 cents from every Shamrock Shake sold will be donated to RMHC and its network of local chapters in celebration of our founding and forever partnership that started 50 years ago ❤️