We do a lot of celebrating in December...
I'm Jewish, DP is Catholic.
What we generally do is give the "big" gifts for Winter Solstace/Yule, since the solstace is pretty universal and not religious. We started this tradition before DS came along. (So far, for DS they haven't been that thrilling... his first year it was a baby gate for around the fireplace, I don't remember the second year, last year it was a $30 train set and this year will likely be his twin bed.)
We light candles for Chanukah. On the first night, we give DS a few small gifts, including clothes, CDs and maybe a DVD.
For Christmas, "Santa" brings small gifts such as matchbox cars, and books, and some sweets including a little candy, an orange and nuts.
Our extended families celebrate separately with us - we go to the IL's on Christmas day and DS gets gifts on that day from grandparents, aunts, uncles.
We get together separately with my mom and dad during Dec or early Jan to celebrate Chanukah. then, later in Jan we get together with my mom's extended family, but it's only barely connected to Chanukah at that point - but the gifts are generally wraped in blue and silver.
DS is African American, so I'm sort of working Kwanza into the mix, but very, very slowly at this point.