Too easy.
I don’t know if it really counts as “funny”, per se, but the
Battle for Castle Itter is certainly the
strangest battle of World War II.
TL;DR: US soldiers, German Wehrmacht soldiers defying orders, an SS defector, a member of the Austrian Resistance, and some French Political Prisoners put up a valorous defense at the title castle, which had been a prison up until then, against an SS Panzergrenadier division that outnumbered them greatly, and
won, in the five-day interim between Hitler’s suicide and the official end of the War in Europe.
Sabaton even wrote a song about it!