Short answers, pulled from the story.
Czechoslovakia was founded in October 1918 as a successor state to the Austro-Hungarian Empire. It formally dissolved on the 31st of December 1992, splitting peacefully into the Czech Republic and the Slovak Republic.
Tomáš Garrigue Masaryk was the first president of Czechoslovakia. He served from the 14th of November 1918 to the 14th of December 1935, when he was succeeded by his close ally Edvard Beneš.
In 1938, the Munich Agreement ceded the Sudetenland to Nazi Germany. By March 1939 the country had been dismembered into the German Protectorate of Bohemia and Moravia and the Slovak State. Czechoslovakia was reestablished after the war in 1945, though Carpathian Ruthenia was ceded to the Soviet Union.
The Prague Spring was a period of political liberalization that began when Alexander Dubček was appointed First Secretary of the Czechoslovak Communist Party on the 5th of January 1968. It ended when Soviet troops, joined by forces from Bulgaria, Poland, and Hungary, invaded on the night of the 20th to the 21st of August 1968.
The Velvet Revolution began on the 17th of November 1989. Eleven days later, on the 28th of November, the Communist Party leaders and the Presidium resigned. The transition was peaceful, and democracy was restored without armed conflict.
Emil Zátopek won four Olympic gold medals in athletics and is considered one of the greatest athletes in Czechoslovak history. Věra Čáslavská won seven Olympic gold medals and four silver medals in gymnastics across three consecutive Olympics. The national football team reached the FIFA World Cup final in both 1934 and 1962, and won the European Football Championship in 1976.