I asked my parents for a DNA test for Christmas...as did a ton of other people. It took a bit longer than the 4-6 weeks because of how many people sent in tests after Christmas. But I finally got my results. I was hoping for a fun surprise but it was pretty much what I thought...I am really fair skinned.
It's fascinating. I want my whole family to have theirs done because two siblings won't have exactly the same DNA. You get half from your dad and half from your mom. So there may be something that you didn't inherit that your sibling did.
See this article for more info http://genetics.thetech.org/ask/ask166:
"You get 50% of your genes from your mom and 50% of your genes from your dad.
Essentially you have two copies of each gene -- one copy from your mom and one copy from your dad. Here is the strange part, the copy that you get from your mom may or not be the same copy that your sibling gets from your mom.
Remember each of your parents has two copies of most of their genes too. When the egg or sperm that made you got made, only one copy of each gene was put in.
The copy that gets put in is chosen randomly through a process called meiosis. What this means is that you have a 50% chance of getting one of their two copies.
That probability doesn't seem impressive until you consider that you have around 25,000 genes. Throw in a 50% chance of getting one copy versus your sibling getting another copy and that makes meiosis a serious gene scrambler.
So, because of this scrambling you and your siblings are 50% genetically identical and are not 100% biochemically identical."