One of the well known Thai dishes, Pad Thai, is actually not very Thai at all, as it was introduced by the Chinese immigrants in the 20th century. After the Second World War, the government tried to create employment by boosting noodle production and noodle shop opening. The ethnic Chinese immediately took up this opportunity and added a noodle dish to their list with flavors, liked by Thai: Pad Thai (Thai style stir fried noodles). Pad Thai is very popular in the United States, where they use tomato ketchup in the sauce, thus creating their own "Pad American".
Even though the Thai have always remained independent and as a consequence, there recipes have less influences from abroad than others, still you find traces from China and India. Mussaman curry for instance was imported by the Muslim community in India.
Special days and remembrances in Thailand, on which you may serve these dishes, are the 16th of January, Teachers' Day; 14 April, celebration of the Mekong Water Festival; 18 August, National Science Day, 20 September, National Youth Day and 23 October, the dying day of King Chulalongkorn (Rama V) (1910). Click on culinary calendar for more links between cooking and worldwide history.