Pretend that you are a visitor to your learner's home country, and that you know nothing about it. Have the months of the year written on a piece of paper, and ask your learner to go through the year and tell about the holidays of each month. You could even break this up and do a different season over four sessions. Talk about the name of the holiday, what it celebrates/commemorates, how people celebrate, what they eat, etc; he or she can even quiz you at the end. You can also use this as an opportunity to talk about any American holiday traditions that may be unclear or confusing to your learner. Both of you will learn a great deal from each other.