Looking for ruins? Pick a Tipiyokti and start climbing DAVE BARRY ATHENS -- Greece today is a modern nation, defined as ''a nation where pretty much everybody is talking on a cellular telephone.'' But there are ghosts of another Greece here: the ancient civilization that gave the world such precious gifts as democracy, philosophy, water, television, Greek salad and the Pythagorean theorem, without which -- incredible as it seems -- we would not have the hypotenuse today. The most visible symbol of the glory that was ancient Greece is the Acropolis, a great big rocky hill that looms above downtown...