Much like handed down family recipes, it's common to hand down family traditions. So, one great thing to do for family history is to record the traditions and how they started.
For example, in my family, we do a big dinner on Christmas eve, and just eat leftovers on Christmas day. This started with my grandma, because my grandpa didn't want her spending all day on Christmas working in the kitchen. So, they decided she'd get the day off, and they moved the big feast to the night before. We still continue this tradition and I have never had to cook on Christmas. As a child I never knew the reason we did that, I just assumed it was so we'd spend one day with my mom's family and the other with my dad's (we lived close to both sets of grandparents).
It's good to find out the origins of family traditions and record them for future generations.