The usual 'tradition' for most people I've know is on Christmas Eve, you open 1 present, then on Christmas day, open em' all.
I've never opened a present on Christmas Eve.
Christmas Eve is just a named day, it's not actually a holiday, so, we don't really do anything for it.
Infact, most people I know will be working on Christmas Eve. And a fair amount of people even do late shopping on Christmas Eve. We'll still be wrapping presents too.
Then on Christmas day we follow a general tradition of getting up around 7-9pm, going through our stockings together, then relaxing a little bit while a lovely Breakfast is made. Sit down to that as a family, and then once were done, we move into our living room and open presents for the rest of the morning.
Then the rest of the day is playing with or using presents or just relaxing and hanging out with the family.
We tend to have a buffet-style dinner on Christmas day, and that follows for a few nights.
We'll have a proper christmas dinner around New Years.