My favorite tradition- you can open one present on Christmas Eve (usually before going to the candlelight service at our church). It was usually enough to tide us over until the morning.
Everyone has to be up before you can open any presents, stockings were free game while waiting for the 'rents to get up and were opened first (a Toberone bar and a Lifesavers story book were very common stocking stuffers, along with batteries and other things that were clues to big presents).
We never wrap things in the box that they belong in. I've gotten shirts in cereal boxes, a watch in a shirt box, a book in a camera box (left over from last year)... never believe the box. We always pull pranks on one another. One year we set up a scavanger hunt through the house for my sister (her first present took her to the kitchen, then that took her to the bedroom, then the basement... until she finally got her real present in her bedroom). Another year my dad borrowed a bread maker box from a neighbor (my mom made it clear that SHE didn't want a bread maker, but my dad did). Christmas morning, she finally caved and got him a breadmaker, and opened her present from him and saw that it was a breadmaker too, finally opened it up the rest of the way and it contained a brick (for weight) and her favorite perfume. :)