1. Thomas Edison/Nikola Tesla invented the lightbulb. (Incandescent light bulbs were being played with by 22 other inventors, and Edison bought the patent for it from Heinrich Goebel's widow.)
2. Christopher Columbus discovered America. (He was one of the last explorers to reach America; not counting the natives already here, Leif Eriksson was the first.)
3. Abraham Lincoln was strongly against slavery. (Only in the Confederate states; if he could save the Union without freeing slaves, he said he'd do it.)
4. Humans evolved from chimpanzees. (We share a common ancestor, but it actually formed two separate lineages.)
5. There's no gravity in space. (There is and it's significantly weaker than what we experience on Earth; it keeps the moon in place and objects that seem to defy gravity are actually in a free fall.)
6. There were 13 original colonies. (There were only 12 - Delaware was a part of Pennsylvania.)
7. Everything about Thanksgiving. (The only thing pilgrims shared with the natives was disease.)
8. The founding fathers were all Christian men. (Only two were Christian: Alexander Hamilton, and that was only after his son was killed, and John Adams, who was Unitarian. Thomas Jefferson and Benjamin Franklin were both deists. George Washington followed pantheism.)
And the BIGGEST lie?
You can be anything you want to be.