There’s a tradition for some college (and adult) atheist groups on Friday the 13th. They will hold an event called a “Superstition Bash.”
The groups will get a table and sit in a public area. Their purpose is to show we shouldn’t give much thought to silly superstitions. Maybe there’s a ladder nearby that you can walk under, or a black cat you can pet, or a small glass mirror that you can break with a hammer (safety precautions are used, of course).
My favorite is when groups bring a hair dryer and offer to “de-baptize” you. Obviously, it doesn’t do any such thing, but the symbolism might be meaningful to some.
What other suggestions do you have for superstitions we can bash today?