I've had parents come in to speak about the holiday that they celebrate in the winter. We study several different holidays in class and the kids enjoy having their families come in to talk about their traditions. I send home a letter asking the parents if they'd like to come. If they say yes, I give them a call to give them the details. I listen to what they'd like to share first (some can be more involved than others) then I let them know how long they'll have. We plan out their visit there on the phone. I haven't had many parents do this because many of our families are quite univolved
but those who have come have really enjoyed the experience!