It's struck me for a while that we could do with something with a bit more energy than the Nicene Creed in our worship. Yes it defines many things that are core doctrines, but it's a document drafted in the 4th century, alive to theological issues then, but today we don't face the same issues.
Martin Luther Kings 'I have a dream' speech is one example of a modern 'creed' which isn't just about doctrine, but brings together deeply held principles with practical examples in a vision of how society can be. One thing that can put wind in the sails of the church is a clearly held vision, which we reinforce regularly, not simply of what doctrines we stand for, but what shape of community, society and world we are committed to.
Here is a very clever, and very good, example of a secular 'creed'.