https://www.instructables.com/Different-Time-Zone-Birthday-Reminder/
Inspired by my friends’ tradition of calling each other at exactly 12 midnight on their birthdays, I developed this product out of guilt of missing out on this tiny but precious practice. To make it worse, due to the time difference, I have been calling my friends either too early or too late to wish Happy Birthday. This simple product is a gag gift to give your forgetful friend.