I strained regular plain yogurt (I did 2% but you could do any kind) and ended up with half the volume I started with of thick creamy greek-style yogurt, and about the same volume of super nutritious whey (the clear liquid that collects on the top of your plain yogurt which you should drink, not discard).
My method of straining was to put a mesh strainer over a large bowl, and lined the strainer with paper coffee filters (I never seem to have cheesecloth when I need it). I poured a full 32 oz container of plain yogurt in, and put it in the fridge, uncovered, over night. In the morning, I just flopped the strained yogurt back into its original container, and it really had reduced by half. Once it's strained even fat free yogurt becomes thick and creamy, and it's so good alone, with a spoon or two of your favorite natural fruit preserves, a drizzle of honey, or some fresh fruit.
With the whey, of which I now had about 2+ cups, I put it into my blender with some frozen mango chunks (about 1 1/2 cups), and it made enough for one light and delicious mango lassi type drink, only it was more refreshing than if it had the creaminess of the yogurt solids in there.
Just to sell this process a little more, even with the volume reducing by half, it's much cheaper than buying greek yogurt ($3 for 32 oz strained down to about 16 oz for plain regular yogurt, vs. as much as $7 for 17.5 oz of greek yogurt). And drinking the whey is so good for you, in fact the whey is probably more nutritious than the yogurt solids, containing more protein, healthy bacteria and calcium. I can imagine using the whey for all kinds of smoothie-type drinks. Yum.
There are no digital cameras in my house right now, so the picture is courtesy of my computer, apologies for the lack of image quality.