If I'm angry about something, putting on some Godsmack and screaming my lungs out (in my car) on the way to or from work REALLY HELPS. Something about hearing a jaded dude screaming and screaming along with him really calms my nerves!
If I'm just wound up severely from too much coffee or something (A Daily Event for Me), to calm down, I sit still for a few, take some deep breaths, and eat something with carbs.
To get to sleep at night (if that is considered calm), I have to take medication. I'm on a higher dose now because apparently my body adjusted to the low dose and I sleptwalk out my freaking front door.
So anyway now I'm sleeping just swell and so very calm, if my house caught on fire, I'd not know.