Calling the Anglo-Zanzibar skirmish a war, is pointless. if you want to talk about a REAL short war, i don't think there ever was anything resembling the israel-arab war of 1967, aka the six days war.
in just 6 days, israel has managed to triple it's size, and have killed 21000 enemy soldiers (while incurring only 779 casualties). also, israel stood alone against the combined armies of Egypt, Syria and Jordan (who were also aided by iraq, sudan, algeria and more).

now that's warfare!