PZ Myers claims that he gets along without rituals. As several commenters point out, this claim highly implausible, but the arguments given need a bit of fine-tuning. Early on the suggestion was made that something like (say) morning coffee would be a ritual; and it was (rightly) pointed out that this need be nothing more than a habit, and that a habit does not a ritual make. It should also be said that not all rituals are habitual or routine, either; you can engage in a ritual only once. One of the commenters suggests that people would react strongly to the notion that their attending a special Mass each each year was only a habit or routine. But, of course, attending a Mass regularly is only a habit or routine. The ritual is not attending Mass but the things in which you participate when you attend (whether you attend regularly or not).
Another mistake that seems to be made occasionally in the discussion is the confusion of ritual and ceremony; the latter being a public forum for a particular sort of ritual activity. For instance, a graduation ceremony is a forum for the ritual activity of receiving one's diploma -- symbolically receiving it, since it doesn't matter whether they actually hand you your diploma or just a blank paper standing for the fact that you will be receiving one. A wedding cermeony is a forum for rituals pertaining to marriage, of which there seem to be quite a few -- saying "I do," wedding rings, kissing the bride, and so forth. Ceremonies are in some sense constituted by rituals. But the reverse is not true; without any ceremony at all you can engage in some very common rituals -- giving a toast, for instance, or shaking someone's hand as a sign of respect. It would be exceedingly trying to have to undergo an elaborate public ceremony every time you wanted to shake someone's hand; but that really doesn't tell us much about ritual actions, because you don't need public ceremonies for ritual actions.
So a ritual is (at least) a deliberate action that is both symbolic and has at least a recognizable potential social significance; it shouldn't be confused with habits or routines, nor with ceremonies. Myers is clearly thinking of ceremonies. But it is possible for someone to have gone through life without ever participating (in any way) in an awards ceremony (of any sort), ever doing anything in a marriage ceremony, ever attending a graduation (whether as a student or as a professor or as a parent), ever toasting a friend over drinks or dinner, ever saluting the flag, ever standing during the national anthem (or singing it), ever blowing out candles on a birthday cake or singing "Happy Birthday," ever pausing for a moment of silence, ever attending a funeral, and so forth. All you have to do is eschew any action that is symbolic and that would be recognized as having at least potential social significance. There's nothing impossible about that. It's just extraordinarily difficult for anyone who actually takes the trouble to live in society without being wrapped up entirely in themselves.