We did some paint-your-own pottery, with good success - no matter what a kid does, the cup or plate looks colorful and shiny when glazed. But there is several weeks lead time so you need to plan for that, especially around the holidays.
I also had him make some snack bags for family members who are on weight watchers - counting out 7 of this nut and 5 of that fruit and 2 chocolates and whatever and putting them in a little bag with a sweet label. He enjoyed the activity and they were so well received we had to make refills the next year.
What great projects have your kids made as holiday gifts?