Visit a public space and observe two people interacting for at least 10 minutes. These must be people you DO NOT KNOW. You will need to be able to observe their body language, so if they are seated and you can't see more than half of their bodies, then find a new set of people to observe. I recommend taking notes while you're observing so you can post a thorough response.
Body language includes many, many things, such as facial expressions, eye contact, arm and hand gestures, posture, leg movements, personal space, positioning, physical appearance, artifacts (e.g., jewelry, purse, etc), touch, smell (e.g., body odor, perfume, etc), and silence.
After you observe the conversation between these two people, answer the following question: What is the nature of the relationship between these two people? What examples can you cite to demonstrate how you reached that conclusion?
Your answer can address such things as how long you think they've known each other; whether they are boss and subordinate, friends, or in a romantic relationship; whether they are getting along or annoyed at each other; if they are enjoying their time together; having a serious conversation; etc. Essentially, tell me as much as you can about what you've surmised about their relationship based solely on watching them.