I would def. take him before another episode. It it hard to say whether it is seizures or something else medically wrong.
I had a cat that something similar happened to once. Emphasis on "had" and "once". I just wouldn't wait. I know Christmas is here, times are tough, etc., but the "next time" well, it may be the last.
I suffer from seizures myself and the excessive drooling sounds like a seizure, as well as the jerking. I'm not sure about any other symptoms in a cat as I haven't looked it up before writing this.
I don't think there is something isolated causing it, for it to be happening numerous times. Take him to the vet and see if it can be controlled, whatever it may be. And please let us know, in case we come across it in the future with our own kitties.