The following is a handout I use prior to teaching about Genetics. It allows students to first identify what common human traits they have -- like eye color, or hitchhiker's thumb, or widow's peak; then assess the class for those same traits -- I have them pair up to assess one trait then share out with the class. And then I ask them to go home and talk to their parents/siblings about their traits. Lastly I ask student to try to figure out which traits are dominant and which are recessive. The whole activity takes half an hour to 45 min in class and can be repeated the next day as students discuss genetic similarities they have with their parents/siblings and whether or not that makes the trait dominant or recessive (at least another 15 - 20 min).