Don't like them much. If it's a get together at lunchtime in school it's usually ok, and it doesn't go on too long or get out-of-hand. But I hate going out to dinner in the evening, at some overpriced restaurant in an out-of-the-way place that seems convenient for everyone else, but not me. As we have to pay our own way because school can't afford to pay for it I often don't go to these.
I'm not a fan of secret santa's either but that's a long story.
Jan