For the 3 days and 3 nights following weddings of Tidong people from northern Borneo, both the bride and groom are prohibited from urinating, defecating, or bathing. They believe that custom will lead to a long, happy, and fertile marriage. In order to achieve this, the newlyweds are allowed to eat and drink only very small amounts and are watched very closely for compliance by family members.
Friends of Scottish brides-to-be take her by surprise and cover her with eggs, spoiled milk, feathers, and other disgusting slop and parade her around town. The purpose is to prepare the bride for marriage, because it will make marital problems seem easier by comparison.
Polterabend is a German pre-wedding tradition where friends and family come together for an informal party and break dishes, flowerpots, tiles, toilets, etc., except glasses or mirrors. The bride and groom must clean everything up to symbolize working together through future difficulties. BTW - married men, on average, change their underwear twice as often as single men.