1. The first German serviceman killed in the war was killed by the Japanese (China, 1937), the first American serviceman killed was killed by the Russians (Finland 1940), the highest ranking American killed was Lt. Gen. Lesley McNair, killed by the US Army Air Corps. So much for allies.
2. The youngest US serviceman was 12 year old Calvin Graham, USN. He was wounded and given a Dishonorable Discharge for lying about his age. (His benefits were later restored by act of Congress)
3. At the time of Pearl Harbor the top US Navy command was Called CINCUS (pronounced "sink us"), the shoulder patch of the US Army's 45th Infantry Division was the Swastika, and Hitler's private train was named "Amerika". All three were soon changed for PR purposes.
4. More US servicemen died in the Air Corps than the Marine Corps. While completing the required 30 missions your chance of being killed was 71%.
5. Generally speaking there was no such thing as an average fighter pilot. You were either an ace or a target. For instance Japanese ace Hiroyoshi Nishizawa shot down over 80 planes. He died while a passenger on a cargo plane.
6. It was a common practice on fighter planes to load every 5th round with a tracer round to aid in aiming. This was a mistake. Tracers had different ballistics so (at long range) if your tracers were hitting the target 80% of your rounds were missing. Worse yet tracers instantly told your enemy he was under fire and from which direction. Worst of all was the practice of loading a string of tracers at the end of the belt to tell you that you were out of ammo. This was definitely not something you wanted to tell the enemy. Units that stopped using tracers saw their success rate nearly double and their loss rate go down.
7. When allied armies reached the Rhine the first thing men did was pee in it. This was pretty universal from the lowest private to Winston Churchill (who made a big show of it) and Gen. Patton (who had himself photographed in the act).
8. German Me-264 bombers were capable of bombing New York City but it wasn't worth the effort.
9. German submarine U-120 was sunk by a malfunctioning toilet.
10. Among the first "Germans" captured at Normandy were several Koreans. They had been forced to fight for the Japanese Army until they were captured by the Russians and forced to fight for the Russian Army until they were captured by the Germans and forced to fight for the German Army until they were captured by the US Army.
11. Following a massive naval bombardment 35,000 US and Canadian troops stormed ashore at Kiska. 21 troops were killed in the firefight. It would have been worse if there had been any Japanese on the island.