Making yogurt at home is incredibly easy. You don't even need any special equipment. The only thing that matters is using a good starter (aka "culture" or the combination of beneficial bacteria).
For context, I have been making my yogurt for 15 years now and started doing that simply because I missed eating decent yogurt. Nothing in the store was good enough for me: too much sugar (any sweetener is too much in yogurt in my opinion), too little fat, too much water and/or gelatin, no acidity whatsoever, not to mention few beneficial bacteria... I can't even count all the yogurt "sins" committed out there. Granted, today there are a few better choices available, but still not enough outside of ethnic or specialty stores in metropolitan cities. So I continue making my own. (Maybe it seems weird that I am SO passionate about this, but I originally come from another country, one of those that are often claimed to have created yogurt and the only one, as far as I know, that has its name included in the Latin name for one of the critical yogurt-making bacteria. You must understand... )
Anyway, back to the technique I use:
1) Take half a gallon of whole milk (1% and 2% would do as well; skim is really not recommended; you could mix with cream and whatnot but really don't need to; I also use and recommend organic). This will produce two 32oz containers of yogurt in the end.
2) Heat the milk in a large pot, just until a foam starts to rise. Turn the heat off immediately and remove the pot from the burner (you don't want the milk boiling + if you are not watching it it WILL boil over in an instant and make a sticky mess). For this amount and setting my burner on medium-high to high, this takes about 15-20 minutes. You want to be watching it to catch the moment when the liquid starts bubbling and rising.
3) Let the milk cool down to 100 or so degrees F (temperature you'd bathe a baby in if that's a reference that means something to you). I don't use a thermometer, but do the "pinky test": dip your CLEAN finger in the liquid: if it feels comfortable, you're good to proceed. If too hot, wait a few more minutes and try again. You don't want the liquid to fall below 90 because the bacteria will have a harder time working well then. Again, for this amount of liquid, the waiting time is about 30-40 minutes.
4) Take one of the containers you'll be storing your yogurt in (Weck glass jars are great, but if you're just experimenting and don't want to invest in new stuff, just use two large plastic containers from yogurt you've previously bought from the store). Mix your starter (I'll discuss this below since it is the most important choice to make correctly) with two ladlefuls of the warm milk. Whisk (a fork will do too) well until everything is well mix and the texture is smooth again.
5) Slowly pour the mix from the container back into the larger pot, while constantly whisking. I like to make figure eights in the pot with my utensil, for best distribution of the cultures across the whole volume.
6) Split the ready liquid among the containers you will be keeping the yogurt in and close. Wrap each one in a clean plastic bag (good way to reuse any stray ones you might have picked up at the grocery store; you want something that doesn't "breathe" but will retain the heat longer).
7) Find a warm-ish place in your house where the yogurt can sit undisturbed a certain number of hours. (I keep mine in the oven, turned off of course. Another easy option is an empty cooler.) Cover with a blanket. Let rest anywhere from 8 to 24 hours. The longer it rests, the tangier the taste will be and, in some cases, depending on the starter, the thicker the texture.
8) After 8 hours, feel free to taste to see when you are happy with yours. Once it reaches that point, unwrap and put in the fridge. Enjoy!
About the starter: the old-fashioned way to do this is to keep half a cup or so of your previous yogurt to use as a starter. This is obviously not an option the first time you'll be trying this but, more than that, I personally prefer to eat every little drop of my yogurt and not to have to "save" any. So I buy this prepackaged starter, which creates a fantastic taste PLUS (and this is important) is very consistent: http://www.yogourmet.com/usa/yogurt-starter-culture.php. You can find it, among other places, at Whole Foods, Amazon.com, Drugstore.com as well where the price is often better when you buy multi-packs.
I will be so happy to hear the experience of @rgcainmd or anybody else who might get inspired to make their own. (And, since this thread is actually about gut health -- real yogurt made this way is chockfull of probiotics and great for your overall health + for me anyway, it does not need carb coverage, though you should check how it affects you.)