How to Liven Up a Party

Tell folks about the actual history of the institution of marriage. This has never failed to start a shouting match at even the most relaxed gathering.

From Reason:

Statistically speaking, Coontz observes, the most "traditional" form of marriage is not "one man, one woman" but "one man, as many women as he can afford." Many Native American groups cared about diversity of gender in marriage rather than of biological sex: A couple had to comprise one person doing "man's work" and one person doing "woman's work," regardless of what their genitals looked like. The unique Na people in southwestern China live not in couples but in sibling clusters, with groups of brothers and sisters collaboratively raising the children conceived by the women during evening rendezvous with visitors.

What's most striking, however, is the panoply of purposes marriage has served at different times and in different places, even when Coontz focuses on the more familiar one-on-one heterosexual union.

Among early hunter-gatherer bands, the trading of members to other bands as spouses was, above all, a means of establishing networks of trade and economic cooperation. Once each group had members with loyalties and ties to both, barter became a safer bet. As Claude Lévi-Strauss put it, the "reciprocity which is the basis of marriage is not established between men and women, but between men by means of women, who are merely the occasion of this relationship."

Try it, it's fun. I have put the occasional Mormon into an apoplectic fit with this.