There is a similar tradition in the U.S., although it is much more of a children's game. If two people say the same thing at the same time, the first to say "jinx" is allowed to subject the other person to some sort of silly rule for the rest of the day. I have heard of many variations of this game.

Don't Sing at the Dinner Table

In the Netherlands, singing your favorite tune means you're singing to the devil for your food.

Don't Sit at the Corner of the Table

Another act causing you to be barren in the marriage department? Sitting at the corner of the dinner table, according to Hungarian and Russian superstitions.

Don't Wear Red During a Storm

In the Philippines, it's believed that the color red attracts lightning.

Don't Enter a Room With Your Left Foot

In Spain, walking into a room with your left foot will bring you bad luck. It's always better to enter or leave with your right.

Eat Grapes on New Year's Eve

In Spain, instead of kissing someone at midnight to celebrate the New Year, they're encouraged to eat 12 grapes one after the other for good luck.

Hide Your Thumbs When Passing a Graveyard

People tend to hold their breath when they pass cemeteries, but in Japan, you must tuck your thumbs in to protect your parents.

Don't Step on a Manhole

We all know the phrase: "Step on a crack, break your mother's back." But in Sweden, you have to watch out for manholes. If you step on one with the letter A, this will bring you a broken heart and bad luck.

In my neighborhood the first one to say jinx was allowed to punch the other guy in the bicep. Very similar to the game of Pediddle where a passing car with a missing headlight provides the trigger.

3rd on a match is bad luck.
Comes from the Great War where lighting a smoke could get you a fast bullet from a Sniper!

Don't Trim Your Nails at Night

Many cultures believe that cutting your nails after the sun goes down is a big N-O. According to U.S. News, one Japanese superstition states it can cause premature death.

Are these superstitions cumulative? If only a 10th of the ones in this thread are true I died, horribly, sometime in 2011. :hmmm:

Can't say for certain because I know of nobody living who has had personal experiences of them :)

Don't Chew Gum at Night

In Turkey, chewing gum at night is apparently the equivalent of chewing on the flesh of the dead.

That's really weird.