What do Wiccans do on the full moon?

My friend has recently denounced his Christian faith and is now a Wiccan. I'm curious about his new lifestyle, and he invited me to a thing that Wiccans do on the full moon. It's tomorrow. He won't tell me what it is, because he wants me to experience it without any biases . . . or something. Any Wiccans here? What happens on the full moon?