Pick a disorder or health condition that interests you (e.g. heart disease, diabetes, depression, obesity, etc.). Do some research into the condition and find a health intervention (i.e. some sort of attempt at changing behavior in a way that promotes good health) that has evidence to support it being used to prevent the occurrence of the disorder. Then, devise a health promotion effort that is based on one of the theories that could be used to convince a group of people to participate in the new healthy behavior.