Answer by
LeheckaG (1826)
"Hens-night" is a United-Kingdom (and former-United Kingdom, like Australia) term;
it has the same meaning as "Bachlorette-party" in the United-States, "stagette" in Canada,
a dinner-party for a woman who is about to get married.
"Hens-night-games" refers to the "adult" party-games which women play at such a bachlorette-party.
The male-version is a bachelor, buck, bull, or stag party.