You can show a television show or news report in class while it's being broadcast if it's important to the lecture and is being broadcast at the same time.
Keep in mind, this privilege does not extend to home cable TV, "on demand" subscription services which have licences that set out the terms and conditions of use. (iTunes, Netflix**, Bell Satellite TV, Rogers Anytime TV, Shomi, CraveTV, etc.) cannot be used in class due to licensing restrictions.