Family events can be awkward and uncomfortable for various reasons. You might not be able to be honest about your feelings, however, without creating conflict with your family members. In this situation, your best bet is to create excuses to get out of family events. You shouldn't flat-out lie, as some nosy relative will surely expose you; however, there's nothing stopping you from keeping track of upcoming family events and making alternate plans.
Find out when and where family events will occur. If you can, ask relatives to inform you of upcoming events by e-mail, that way you won't have to make up an excuse on the spot, as you would with a phone call.
Consider the date, time and frequency of the event. This will help you create a better excuse. "I'm sick" might work once, for example, but not if it happens every other Friday.
Change your work schedule to conflict with upcoming family events. This works best if your job has an irregular schedule rather than a 9 to 5 workday, since you can always blame your boss for moving your shifts around or calling you in on short notice.
Join a club or organisation that conflicts with a recurring family event. Again, you have the excuse that you don't set the schedule -- it's just the day and time that works best for most people in the club.
Stage a transportation mishap, if your family lives far enough away that no one can come pick you up. "I can't afford a plane ticket" is a good excuse not to travel long distances, while an automobile mishap is good for last-minute cancellations.
Make plans with someone else's family for annual family events, such as Christmas or Thanksgiving. If you enjoy spending time with your spouse or partner's family, having plans with them makes a very believable and sympathetic excuse. You could also convince a good friend to invite you to her family gathering instead.
Spend time with whatever family you can. If you want to get out of family events because of a few people who make you uncomfortable, make plans to visit the family members you do like. This will help convince people that you're not just trying to avoid them, but really are busy during family events.
Avoid flimsy or outrageous excuses. "My toddler ate my car keys" might seem funny at the time, but if you always have an excuse like that, people will get suspicious.