L.P. Benezet was the superintendent of the Manchester, NH schools in the 30's. He decided that there was a big problem with math instruction and decided to delay formal instruction in math until 6th or 7th grade. In the earlier grades the children still learned about days of the week and month, time, money, estimating, measuring, and so on. They also focused more on reasoning and communication skills.
The complete articles, which were originally published in the Journal of the NEA, can be found here. I read the Math Forum, and saw Benezet mentioned. I posted a topic there to gather information, and another to discuss pros and cons. But the folks there insist on flaming each other, so it's a bit tedious.
Anyone here know anything more about his experiment?