Thanksgiving is special to many people because they get to see their extended family or even just their family of origin. Thanksgiving is not a religious holiday, but it does have spiritual overtones thanks to the prayers being said, so some people consider it "not PC" to talk about it at work or school. Thanksgiving is a bigger concept than just the story of the founding of the Plymouth Plantation, but you can leave it at that if you want to avoid a more spritual theme.
Thanksgiving is celebrated in North America, and is generally observed as an expression of gratitude for all of the good that has come the way of the family that year. Many non-religious people say a prayer of thanks to the "higher power" at Thanksgiving. The most common view of its origin is that it was to give thanks to God for the bounty of the autumn harvest and that the American holiday was just a way of incorporating the Pagan harvest feast such as Oktoberfest. Thanksgiving is a time to reflect and be grateful for what he have.
Thanksgiving is thoght of by many as a cooking and eating and football watching holiday. A large turkey meal with festive Thanksgiving dinnerware and decorations is often prepared for family and/or friends. Thanksgiving is a holiday in Canada, as well as in the USA, and is celebrated on the second Monday in October. Thanksgiving is a uniquely North American holiday, because this country is the only place to celebrate it. Many other countries do not even eat or like Turkey. It is America that has been the beacon for anyone wanting to escape from poverty and misery.
Thanksgiving is also one of the busiest Christmas shopping times as well as a busy travel time and a time for many to put out their first Xmas decorations.