Short answers, pulled from the story.
The Phoney War was an eight-month period at the start of World War II, from September 1939 to May 1940, during which there were virtually no major Allied military land operations on the Western Front. It began when Britain and France declared war on Germany on the 3rd of September 1939 and ended with the German invasion of France and the Low Countries on the 10th of May 1940.
Credit for coining the term is generally given to U.S. Senator William Borah, who said in September 1939 that "there is something phoney about this war." The first known printed use appeared in a U.S. newspaper in September 1939 using the British spelling, and the term first appeared in British print in January 1940.
The Saar Offensive was France's only offensive land action during the Phoney War. Beginning on the 7th of September 1939, eleven French divisions advanced along a 32-kilometre line near Saarbrucken and pushed up to eight kilometres into German territory. The French withdrew by the 17th of October 1939 after General Gamelin ordered troops back to the Maginot Line.
The Soviet Union's attack on Finland on the 30th of November 1939 triggered intense debate in France and Britain about mounting an offensive to help Finland. Allied forces were assembled but not dispatched before the Winter War ended in March 1940. The Allied discussions about a Scandinavian campaign alarmed Germany and contributed directly to the German invasion of Denmark and Norway in April 1940.
Chamberlain resigned the premiership on the 10th of May 1940 following the disastrous Allied campaign in Norway. A vote of confidence in his government passed by only 281 to 200, with many of his own supporters voting against him or abstaining, making it impossible for him to continue leading a National Government. Winston Churchill succeeded him the same day.
Most combat during the Phoney War took place at sea. On the 3rd of September 1939, a German submarine sank the SS Athenia, killing 117 people. On the 17th of September, a British aircraft carrier was sunk with the loss of 519 crew. On the 14th of October, a German submarine penetrated Scapa Flow and sank a British battleship, killing 833 men including Rear-Admiral Henry Blagrove. At sea, the Battle of the Atlantic had already begun.