I'm a Christian, I should make that clear now. Makes for a slightly more interesting view of the universe, being a rather dark being in the service of the God of light and all.

However, forgoing an indepth theological discussion, I wanted to describe a rather good centering ritual which I use.

Generally, I sit cross-legged, hands resting in my lap, palms cupped upward, to form a sort of bowl.
Into this bowl, I then start an energy flow, which pools, and then begins to smoke, as a sacrifice (which although no longer necessary, is still a gift freely given).
With my eyes closed, and this energy burning, I clear my mind of all the clutter, and I then make my prayer - generally, a thanks for what I've been given, a rededication to the path I am attempting to follow, a request for help along this path, and possibly a few requests for the future.

Once this is completed I then generally receive a larger portion of energy back through the heaven-line, and I finish.

And oddly enough, my requests often come true - or when they don't, I get something better.