A sample of serendipity: a rare metal and the year you were born.  

Dysprosium, is used in your EV, your mobile phone and in nuclear reactors, has an atomic weight of 66 and its pure form was isolated around 1955.   

Your birthday?  Let’s use those numbers:
Subtract your age from the number 66.  
Then add 1955.
You’ll get the year you were born.

Sometimes you find fun without looking for it. Enjoy your day.