When I was little, we always either had our big extended family at my house or my godmother's for Christmas Eve. We'd have our huge dinner, all the cousins would go to Midnight Mass (we ranged at that time from 10-30 years old) and then come back and open gifts. We'd get home about 4am (or everyone would leave by) because the adults were playing cards and us kids were doing whatever. Then in the morning we'd open up our immediate family and Santa's gifts, and then get ready to do the whole dinner thing all over again at my godmother's. That tradition slowly stopped and now no one gets together because the cousins are all married with their own families. I get to open a few gifts on Eve because I always get upset about our tradition being gone, and then my brother comes over with his family on the day and we open gift. This year I got all my gifts a week early.

my mom wanted to start that this year, and we ALL vetoed that mess. but ive seen this on this thread a couple times. is that common, families wearing matching pjs and taking pics?

We always opened stuff on Christmas, but recently it has become more a matter of when we can all be together -- if that's even possible.

This year, for instance, all of our kids were in town last week and wife's mother and sister were as well, so we opened presents on December 17.

When we were little kids our family followed the French tradition. Midnight Mass on the 24th followed by a 2AM seafood feast and a stocking or container of some type filled with small presents from Pere Noel. Big dinner on Christmas day but more focused on the birth of Christ than on presents. The tree went up on Christmas Eve and stayed up until the day after Twelvth Night (Kings Day).
The main gift giving was on Twelvth Night to celebrate the arrival of the three Kings who brought gifts to the Christ Child. This was called Petit Noel and was our big day of anticipation.
We still keep the same schedule with the tree and the seafood feast after midnight mass but have pretty much shifted the gift giving to Christmas morning.

Like many have said, when I was growing up we opened one on Christmas Eve and the rest on Christmas Day. We didn't do the pj thing, but usually the one we got to open Christmas Eve was a sweater or something that my aunt made and wasn't much fun. Then Santa came that night and we opened all the fun stuff Christmas morning.

Now it's basically whenever we get together. Mr. SSS and I went to my parents' house on Dec. 16th this year, and we all exchanged gifts then. We spent Christmas at his parents' house. He has 10 brothers and sisters, so we do a Secret Santa for all the siblings and we exchange the Secret Santa presents on Christmas Eve. Everything else is pretty much Christmas Day, except this year one of my sisters-in-law and her husband and daughter (she's almost 2) opened all their gifts Christmas Eve because they were spending Christmas Day at her husband's parents' house. Then of course my other niece got to open a few too, so she wouldn't feel left out (she's only 4 and wouldn't understand why she had to wait while her cousin got to open gifts).