This pair of busy, weekday lunch-only spots near Government Center offer a gyro sandwich that many Americans have never tasted, the most popular version in Greece: not the usual nasty factory-made ground-beef/lamb cone, but slabs of marinated pork stacked, grilled and sliced off a vertical rotisserie. It’s a revelation, generously stuffed into superb pita with great tzatziki. Repeat customers will want to sample the equally fine chicken gyros, hearty lamb chili and big, healthy salads (that you should probably top with gyro anyway).