German Wedding Traditions: Polterabend
The Polterabend is a (German) tradition normally held the night before the wedding or a few days earlier. It is basically a large (informal) get together where the guests bring old dishes along to smash into little bitty pieces for the couple to clean up. The party also serves to celebrate with people that could not be invited to the reception.
In the olden days legend said that the noise of the breaking dishes drove evil spirits away, hence the word Polter as in Poltergeist 
“Polter” actually describes the noise you hear from smashing the dishes.
The smaller the pieces of porcelain, china etc. the more luck the couple is said to have. This might be comparable to the Jewish wedding tradition where the groom must smash a glass with his heel in one go for good luck. In the German tradition glass brings bad luck, so people only bring china and porcelain.
Sometimes guests might show up with a Mack truck full of dishes (luck or not)! Also the couple should make sure to hide the pieces that have been collected, as the guest might try to spread it all out again.
The broken pieces can be used to decorate a vase afterwards and create a nice keep-sake.
In between clean ups there should be time for mingling, food and a bit of bubbly!