We open one gift on Xmas eve - the rest on Xmas morning.
At my house you have to believe in Santa or you don't get the gifts that are marked from him. And really, who doesn't believe in Santa at Xmas?
Since my DH is Jewish my mom always buys him funny "jewish" gifts. Coffee mugs with menorahs, star of david chocolates, etc. Totally useless crap - but it makes me laugh. He's not religious so it's not offensive or anything.
Also, we believe that Xmas eve is the only day of the year pets can talk. Random, I know - but it's always funny to wait and see what the dogs say. Odd that they have never piped up.
DH and I started our own tradition of buying a new xmas ornament every year. It's an easy way to build a collection of ornaments - and it's fun to look back at the ones we have.
Oh! We also "hide" a pickle ornament on the tree. Whoever finds it has good luck for the next year.