I have tried to incorporate some made-up religions to my sims' life. I have community lot churches, clubs and now also someholidays that tie into their beliefs. It's still a work in process.
In Founder Sim's Church they think there was a founder sim who was their ancestor. They're rather conservative, at least the core group that lives in Oasis Springs. They also believe that all worthy sims will be saved to the gallery and have a chance for a second life. This all could of course be true, but my save doesn't have a founder sim and I don't generally bring sims back...
The plumbobians belive that there's a plumbob that sometimes appears over the sims head and it will give their lives a direction. Most believe that the plumbob is green and means good, but some worship the red plumbob. This is kind of like the state religion. Almost all sims who don't belong to Founder Sim's Church will be buried in one of the plumbobian cathedrals. This religion isn't as well shaped in my mind as the other, probably because there are so many sims that it should suit.
I have tried to create even a third religion, perhaps a nature religion, but I feel like I can barely manage two.
