Online retailer, amazon.com recently submitted a patent for a "gift converter." The program would let you set up a wish list and parameters for your gift receiving.
So say your uncle gives you a Blue-Ray disc of a movie you want, you could tell the gift converter, you only want DVD's and it would convert the gift. You can also set limits on the amount of one type of gift you get, so you don't get 50 pairs of socks.
Any difference in costs would be credited to the recipient in the form of a gift card.