To which I say, just don't do it. Atheists pray lousy, as I have pointed out before in these pages. Asking an atheist to pray is like asking a rabbi to make a pulled pork sandwich. He doesn't have access to the basic ingredients, has only a vague idea of how to hash them together and can't enjoy the final result. The rabbi can at least pray for guidance; for the atheist, that would only compound his difficulties.
A religious person often begins his prayer with "Dear God," a customary salutation for a business letter or, back in the days when they were written, a personal one. As email becomes more deeply embedded in our daily lives, this could eventually be replaced by "Hey God." No matter; the salutation does not present a problem for atheists. It is the Being being addressed that the atheist stumbles over. A religious person, after saying "Dear God," just prattles on, asking the alleged Creator of the Universe basic prayer stuff, anything from world peace to a fervent wish that his next door neighbor, an attractive young woman, will continue to practice yoga in the nude without drawing her blinds, to civil harmony and prosperity for, say, Greece, New York. If the last is the case, then the prayer can be concluded quickly and everybody can get to the business of the town meeting, which for most of the participants is wishing that it was already over.
The atheist may begin his town council prayer with "Dear God," but then he loses his way. He has to add "If You exist," and upon further reflection, a whole list of other qualifying phrases like, "and if You take any interest in human affairs and if you are aware of us at all, not, as seems likely sometimes, that we sprouted up at the edge of one of Your galaxies like some exotic interstellar fungus utterly unplanned and unsought by You, and if You actually have any inclination, or really, any mechanism to pay attention to me, because I don't see any giant ears orbiting overhead waiting for me to pray into them, and You chose to listen to me instead of any one of the other seven billion souls on earth currently begging for Your intercession in winning the lottery or being cured of cancer or getting a crocodile to stop chewing on them or some other problem much more difficult and intransigent than mine, would You please grant us an orderly and swift town meeting? Amen.
This prayer would vault the opening invocation from being the least interesting part of the town meeting to being the most, although being the most interesting part of a town meeting is pretty much like being the swiftest slug on the sidewalk. I don't think anyone would get much spiritual satisfaction from that prayer, though, least of all the atheist who prayed it. It would make more sense to have an agnostic open the meeting with an agnostic prayer. The agnostic would smile and say "Why are we here?" Then he could pause for a beat and say "We don't know."
Then everybody, to their great relief, could go home.