A few weeks ago there was this link on today I learned. Its about a culture where people have to work cannot play from a certain age and fun is looked down upon. Also they have no religious traditions.
There's actually a very small group of people here in the present who have no religion. Give me a few and I'll look them up to refresh my memory
Edit: the Pirahã! You should look them up. They have no concept of numbers, time, or a deity that they worship. There's a documentary out there about them that's excellent