My family asks me for computer help whenever I'm home, so I don't expect the holidays to be any different. The exception being that when new gadgets are received on Christmas day we generally sit down and learn the object together. It's not easy to "fix" something when it's brand new to me, so there's that as well.
And sure, I don't always feel like fixing a computer or looking into a printer or troubleshooting a fritzy mp3 player, but I do anyway. My family depends on me, and a lot of people do feel truly lost when something with their technology goes awry. All the same, I'm a believer of firm but nice answers. Perhaps a little, "Can we look at it later?" or, "Why don't we find a time when things aren't so hectic." It's important to set boundaries because we (myself and other tech-smart people out there) are home for the holidays and we all deserve to relax, too.
Perhaps more important than learning to say "no" is learning when to admit defeat. I'm not an expert by any stretch of the word, but in many cases I seem like it to my family. They expect me to have answers and solutions, and for my own sanity I need to be able to say that the problem is beyond me and they should seek other options. Of course I hate it when this happens! I want to be able to help, and I get a lot of satisfaction from fixing problems. However it doesn't help me to get stressed and end up ignoring family just to fix one wonky machine.
I realize that my situation probably isn't like everyone else's: I don't have huge extended family holidays. If I'm fixing something then it's only one or two little things for my mom, and she's amazing so I don't mind helping her. Earlier this week I spent an entire day getting her desktop machine in shape and installing a fancy new printer. I know how much she appreciate it, and that makes me happy.
Are you the tech support person in your family? Do you dread holiday gatherings because of it? I want to know!