For me it was every year on Valentine's Day.
I don't know if it as barbaric and cruel now as it was then. The teacher would gather all the valentines at the front of the room. She would call out the name on the valentine and the recipient would walk up to claim it and go back to his/her seat. The popular kids kept going up repeatedly. I think I might have gotten one. I just remember how I wished there were another way to do it. Actually probably no one paid any attention and didn't care. They were too busy with their own valentines. I wonder why after all these years that is the one thing that stands out still from grammar school days?. Did you ever have something like that you had to go through?