From the History Channel - 
 

Which president refused to recognize Thanksgiving?

Thomas Jefferson was famously the only Founding Father and early president who refused to declare days of thanksgiving and fasting in the United States. Unlike his political rivals, the Federalists, Jefferson believed in “a wall of separation between Church and State” and believed that endorsing such celebrations as president would amount to a state-sponsored religious worship. Read more.

What does the poem, 'Mary had a little lamb,' have to do with Thanksgiving?

The first official proclamation of a national Thanksgiving holiday didn’t come until 1863, when President Abraham Lincoln called for an annual Thanksgiving celebration on the final Thursday in November. The proclamation was the result of years of impassioned lobbying by "Mary Had a Little Lamb" author and abolitionist Sarah Josepha Hale.

How did a botched Thanksgiving order lead to the TV tray dinner?

In 1953, an employee at C.A. Swanson & Sons overestimated demand for Thanksgiving turkey and the company was left with some 260 tons of extra frozen birds. As a solution, Smithsonian reports, a Swanson salesman ordered 5,000 aluminum trays, devised a turkey meal and recruited an assembly line of workers to compile what would become the first TV tray dinners. A culinary hit was born. In the first full year of production, 1954, the company sold 10 million turkey TV tray dinners.