Celebrating holidays cross-religion?

In writing yesterday's post I realized that my kids have been excited ever since Hanukkah started. We're Christian, but they go to public school in NYC so there are plenty of kids who celebrate Hanukkah, so they're well aware of when it happens and the basic outline of activities, if not the actual history.

(My older son, in fact, said to me a week or so ago, "Mom, do you think I'll get as much stuff for Christmas as I would have for Hanukkah if we were Jewish?" Which is a funny question, but then when you consider the layers of escalating commercialism on all sides of that equation it starts to make your head hurt.)

So I was thinking that maybe next year in the middle of Advent we'll do some Hanukkah menorah lighting, too, so the kids can get a little cross-cultural history and tradition, remved from the idea of eight nights of presents.

One of my Facebook friends, who is Jewish, said that her son wanted an Advent calendar, and I thought, "Why not?"

So what do you think about celebrating holidays that are not your religion or culture's holidays?

Does it matter if the aspects you celebrate are religious in nature (like lighting candles) or secular (putting up a tree)?

Is it disrespectful? Or bridging gaps?

Will your kids be confused? Or enriched?

Thoughts?