Materials:
A small clear cup
Rubbing alcohol, chilled in your fridge
Dishwashing detergent
Salt
Eyedropper (optional)
Spoon  or stirring stick

What To Do:
Stir about a teaspoon of salt into a glass of water until it dissolves. Take a swig from the glass (wait, don't swallow!) and swish the saltwater around in your mouth for a minute before spitting it back into the glass. This salty, spitty mixture now contains cells from the inside of your mouth. Your DNA is in each of those cells, but how will you get it out? This is where the dishwashing detergent comes in. Gently stir a few drops of dish soap into the saltwater mixture. The soap will break down the cell membranes in the solution, releasing your DNA, for the same reason that dishsoap breaks down oil and grease when you're washing dirty dishes.

Next, very carefully add a few teaspoons of the chilled rubbing alcohol. You should add the alcohol slowly and carefully enough that it rests in a separate layer on top of the salty, soapy, DNA-y water in the cup. This is easiest with an eyedropper, but you can also dribble it down the side of the cup carefully with a spoon. In a minute or so you should see whitish, spiderwebby clumps forming in the alcohol layer. This is your DNA. In the saltwater, DNA is soluble, so it is invisible to the naked eye. However, the strands of DNA clump together in alcohol, forming strands big enough for you to see in the glass.

If you want to save your DNA, you can try winding up the strands on a toothpick, then sticking the DNA glob onto a piece of paper, where it will dry. Perfect for framing!

More:
All living things have DNA. Can you get DNA out of something (parent-approved) in your kitchen--say, a banana? Add a comment to share your results.