We have several. Since my dh is military and we move a lot, I think it's important to have traditions and a sense of continuity. A lot of the things we do my kids have said that they want to do with their kids (mine are now 18 and almost 17) when they're parents.
Here are a couple - every yr, we all get a new Christmas ornament that we each pick out, then I write on the box or the back of the ornament whose it is, year, and where we live. Over the yrs, it's sort of like "memory lane" when we decorate the tree - remembering when, say, they were really "into" this or that, how their interests changed over the yrs, etc.
I say a blessing over them every day before school.
We do "backwards lunch" every year on the last day of school. The kids pick the place, then we all have the most decadent, crazy dessert we want, and talk about the past yr, what they're looking forward to for summer, life in general, etc.
at 8:15 PM on Feb. 1, 2011