Thanksgiving is always celebrated the fourth Thursday of November in the USA. Friends and family gather for a meal, typically involving a turkey as the centerpiece. Common side dishes include sweet potato casserole, green bean casserole, cranberry relish, and sometimes mashed potatoes. Dessert is nearly always pie -- the most common Thanksgiving pies being pumpkin, pecan and apple.
Typically before the meal, people say what they're grateful for. Of course, this would include the other people seated around the table(!), the feast before them, good health, and prosperity.
Enjoy these idioms in honor of Thanksgiving!