For myself, of course, I like the Ten Commitments of Humanism, Developed by the American Humanist Association's Centre for Education.
But of course, we couldn't put them on school walls -- nowhere do they say, "I will amass as much money as possible regardless of the cost to the planet or people and creatures on it."
The Ten Commitments
Altruism: “I will help others in need without hoping for rewards.”
Critical Thinking: “I will practice good judgment by asking questions and thinking for myself.”
Empathy: “I will consider other people’s thoughts, feelings, and experiences.”
Environmentalism: “I will take care of the Earth and the life on it.”
Ethical Development: “I will always focus on becoming a better person.”
Global Awareness: “I will be a good neighbor to the people who share the Earth with me and help make the world a better place for everyone.”
Humility: “I will be aware of my strengths and weaknesses, and appreciate the strengths and weaknesses of others.”
Peace and Social Justice: “I will help people solve problems and handle disagreements in ways that are fair for everyone.”
Responsibility: “I will be a good person—even when no one is looking—and own the consequences of my actions.”
Service and Participation: “I will help my community in ways that let me get to know the people I’m helping.”