National California, Cook a Sweet Potato, and Margarita Day! Today is the day to eat sweet potatoes and sip margaritas in California. Unfortunately, I don't live in California, and I don't like margaritas, but I do love sweet potatoes! It is a good source of Vitamin A, B-6, C, and magnesium! No, a Yam and a Sweet Potato are NOT the same thing despite Westerner's insistence on using the names interchangeably.