We've always fasted and abstained on the 24th, but were told in this morning's announcements at Mass that we could pick -- 23rd or 24th. I'd never heard that before.

I have a prayer book/missal from the 1940s that says that.

On Christmas Eve, we used to go my parents or friends' house before Midnight Mass.  
Feast of the 7 fish in our area.  

This might just be the Hispanic custom of putting Christmas Eve on a higher pedestal than the following holiday, but that was always the day we had Christmas dinner. It certainly wasn't perfect, but my parents did try to kind of live the Faith.

No, this comes from the Jєωιѕн custom. The Jews reckoned the Sabbath as startiong at sundown on Friday night. Therefore when there was a major feast day like Christmas, the evening of the day before is also part of the feast.

Quote from: OHCA

Quote from: MaterDominici

We've always fasted and abstained on the 24th, but were told in this morning's announcements at Mass that we could pick -- 23rd or 24th. I'd never heard that before.

I have a prayer book/missal from the 1940s that says that.

Could your prayer book/missal be a reprint with updates?  I've just read that it was John XXIII that gave you a choice of the 23rd or 24th.

What is the name of your book?

My apologies--I was mistaken.  It calls for fasting on the vigil of Christmas with no allowance for swapping out the 23rd.  I must have seen the 23rd allowance on the traditio site.  You're right--apparently it was JXXIII in 1959.  I'm kind of surprised that that is even referenced on their site since he did it.

My little booklet is The Catholic's Guide.  Looks like it was originally printed in 1924 and I have a 1946 re-print.  But again, I was mistaken about it allowing fasting on the 23rd instead of the 24th.

Pierogi is a traditional favorite in Poland for Christmas Eve.

http://allrecipes.com/recipe/pierogi-polish-dumplings/

Italian Americans traditionally ate fish. I think it's popularly called "Feast of the Seven Fishes."