Did the Buddha teach Engaged Buddhism?

Did the Buddha teach some measure of "Engaged Buddhism", to maybe more of a lay person audience? Did the Buddha ever teach "Engaged Buddhism" to the Bhikkhus? What Buddhist scriptures support Engaged Buddhist teachings? Is it proper for a Bhikkhu to be political in anyway in the world or in the monastery? NOTE: **Engaged Buddhism** generally refers to people who actively **engage** in the world in order to transform it with positive Buddhist ideas & practices.