[FuzzieAlum]

There is a great deal of variation. Obviously, Sigma Chi with its cross, as someone else said, is going to be very Christian. Other orgs have no or almost no reference to Christianity. For example, let's say during pledging there is a line from the Bible read ... but the line says, "Be nice to your fellow man," and that's it - that's a lot different from "Follow Jesus." And other organizations were founded by Jewish women (AEPhi) or to be specifically nondenominational (DPhiE), so while I have no idea what their ritual is, I would guess neither is particualarly based in Christianity.

I have the impression (although I could of course be wrong), that generally, how religious a group is in their public statements is a good indicator of ritual. For example, look at their symbols as well as open motto/symphony/statement.