My father told this at my uncles wedding. He & his brothers decorated the car. They had the bright idea to put one last “Just Married” on the inside of the gas cap cover. (This was back in the day when the driver never pumped gas themself – that was always done by one of the gas station attendants.)
So for months afterwards, they would be telling him congratulations on his marriage. And he was a salesman to grocery stores in small towns all across the western half of Minnesota and halfway across South Dakota, gas pump attendants all across these states were saying this. He’d told most of the grocers, so he was just astonished that in these small towns gossip about him had spread that much. Took him & his wife over 7 months to figure out this, and look for & find the last “Just Married”.
And it wasn’t. They’d also put one below the spare tire. It was over 4 years later, when he and his wife were on a vacation trip halfway across the country, when the service station guy who changed their flat saw that, and congratulated them. (Rather hesitantly, because by then she was about 8-months pregnant with their 2nd child.)
Another from Spain, relatively recent: since money rather than physical gifts became common, the friends of the couple try to come up with some way to give it that’s between bothersome and “I’m going to kill those bastards!”
Some samples:
Collect the money. Put it in a bank account. Said bank account requires two signatures to have money taken out, those of the two friends least likely to succumb to blackmail or bribes.
Buy a huge puzzle. Make it. Write the account number on the back. Break it up again, and hand the box to the couple.
In order to get their money, the couple had to make the puzzle and show it to the two signature-holders: just providing the account number was not enough, as that could have been solved via blackmail or bribe of any of the bank’s workers (it’s a small town, half the people who were doing internships in the local banks that summer were their classmates and the other half were from the other high school).
Turn the money into big notes. Roll each note carefully. Place into a drinking straw. Make napkin carnations. Use the straws as the carnations’ stems. Hand the big bouquet to the bride and groom. This groom was known to be one of those people who, if they tried to cut the Gordian knot, would cut their leg instead. He’d wrecked two notes before being pushed aside by close relatives with more patience for delicate work.
Put the money inside balloons. Inflate balloons. Require bride and groom to dance-stomp them. They actually did manage to make most of the balloon-chasing look like they were waltzing, if a bit jerkily.
Sew notes onto old, smeared clothing and rags (dried oil and things like that, nothing which would actually be stinky or dangerous). Hand the bag holding it all to a couple known by their careful dress.
Some comic once noted that YMCA is, like, the white people’s anthem. It’s true. I have never seen a song more guaranteed to get all of the white people up on the floor flailing about merrily. It’s great! Go white people!
That reminds me of a trick one of my cousins pulled at his wedding (not a tradition yet, but I’d like it to become one, because it was so cool): Every guest at the reception had a question scavenger-hunt, about the other guests, and you had to fill in all the names. “Who once boxed a kangaroo?” “Who used to be in the convent?” “Who once hitchhiked all the way from coast to coast?”, and so on, plus a bonus question of how many different states the guests were from. So everyone was mingling the whole time, especially with the guests from the other side of the guest list, trading answers. Great way to break the ice, when you have two sets of people who don’t know each other at all.
Enter the couple’s home while they are off on their honeymoon and put surprises in the bedroom and bathroom. We TP’d one friend’s bedroom. For another couple, who had renovated an old home, we saved the old, horrid toilet seat and reinstalled it while they were away. Another pair came home to find all their kitchen utensils tucked into the bottom of the bedsheets.
We did something similar at a seminar I once attended. The organizer had asked us all beforehand to send him “three things about you that no one else knows,” and used the best of those, one each, to liven up our initial meet-and-greet.