Ah, it's time for the annual purging of all references to God from schools and history. I guess when they teach about the Pigrims and Thanksgiving now, it goes something like this:
There were some people living in England who, on a lark, decided to embark on a voyage across the dangerous ocean, just because they had nothing better to do, and XBox hadn't been invented yet. So they climbed aboard these leaking, dangerous ships and sailed across the ocean. They played shuffleboard and dined in luxury, but they didn't hit any iceburgs.
When they arrived in America, there were no ports, so they simply climbed into rowboats and landed. They built houses (from trees, there were no Lowe's stores). After they landed, they encountered REAL Americans, the most honorable and non-violent species of man ever to exist, Native Americans, who had been living peacefully, growing corn, for tens of millions of years.
The Pilgrims had three days that they celebrated -- the weekly Sabbath, the Day of Humiliation and Fasting, and the Day of Thanksgiving and Praise. The last two were only held during special occasions. The colonists had had a very bad year for the harvest one year (1621 or so), and they were worried they would all die. When news came that another shipload of supplies and people was soon to arrive, they had a party. They invited their new friends, the Native Americans (at least those they hadn't killed with the smallpox). They all worshipped and gave thanks to the great Rocks and the Ship of Plenty that had carried them to the new land. They wore funny hats. That was the first Thanksgiving.