This week's Cajun thing is a custom that you may never have heard of...
When Cajuns leave a wedding site (church, etc.) and head to the reception site, the entire procession of guests honk their car horns in celebration of their newly married acquaintances.
This custom is loosely based on the the old French custom of banging pots, pans, and anything else noisy in celebration of a newly wed couple. That custom is also known as a charivari. Some articles I've read state that the charivari was also used to encourage couples to marry.
This coming Valentine's Day, try making a charivari for a couple that you think should marry. When they do, you can honk your car horn on the way from their wedding to their reception!