This is a simple activity that I use with my students to work on the vocabulary and making connections to family relations during chapter 5A of the Realidades I textbook. Students love this activity because it uses information they have heard in popular culture. The worksheet itself has a copy of the royal family tree and 10 questions about the relationships between them. ("Who is the grandmother of William?" for example.)
This activity will probably take around 15 minutes for students to complete but you could make it last longer by asking students further questions about the relationships or by asking them to write sentences describing the relationships.
Please let me know what you think!