I am talking about using a couple items you may already have, and one item you probably have to buy. The first item is a beer cooler, the second is zip lock bags, and the third is a stick thermometer. If your cooler can hold ice for an entire football game, I'm not saying to keep the ice totally frozen, but that there still is a good amount of ice in it, it is probably good enough to work. Insulation works just as good at keeping heat in as keeping it out, a driving mug can keep your soda cool as well as keep your coffee hot. The thermometer you can get at Wal-Mart or Target, or through Amazon for $5 for an analog and $10 to $25 for a digital one. You can spend more if you like, and buy a beer cooler just for cooking in, but that's up to you.
Now on to the ribs. What you need is as many racks of ribs as you need, a bar-b-q rub, hot water, and your sauce of choice which is optional. You can cheat with the ribs and rub by buying a sealed pre-seasoned/pre-sauced package of ribs, but not pre-cooked in any way. The bar-b-q rub can be bought at the local grocery, look in the aisle next to the bar-b-q sauces, or by the seasoning section of the market, or you can make your own. A home made rub is fairly easy to make. Take a half cup of brown sugar, a quarter cup of salt, a tablespoon of chili powder, a half teaspoon each of onion powder, garlic powder, and smokey paprika. Mix together well. You can adjust it to your taste, making it sweeter, or spicier as you like.
Take the rub and coat the ribs, rub it in, smack it in, let it get absorbed into the meat. Coat the ribs good. Next step is to place the ribs into one gallon or two gallon zip lock bags. To seal the bag, have a bowl or pot with water, and lower the bag into the water, and let the pressure of the water push the air out of the bag. You want as much of a vacuum as you can get. When you get to the top, seal it 90%, leaving about an inch open, tilt it in the water to push the last bit of air out of that opening, and seal is shut. Try not to get any water into the bag, but a few drops won't hurt.
Now to cooking the ribs. Take the ribs out of the refrigerator so they warm to near room temperature. Get a pot, fill it with enough water to fill the beer cooler, heat it to when it is ready to boil, you don't really need it to boil fully. Take your thermometer, and check the temperature, should be right around 212 degrees (no duh), slowly add room temperature water until the temperature of the water in the pot is between 150 and 160 degrees. Place the ribs into the beer cooler, add enough water to the cooler to cover the ribs, checking the water temperature as you do as the ribs will cool the water, you want the water temperature to be above 150 degrees. Close the lid and go about your day.
One thing I suggest is to check the temperature of the water every 5 to 6 hours. Doing this will let some heat out, so have some boiling water ready to add, stirring the water around so that it gets back above 150 degrees, remove some water if it gets overfilled (this can be reheated later and rotated back into the cooler) . Of another way is to have a cooler just for cooking, get a thermometer that is a meter with an attached probe. Drill a hole in the top of the cooler, and slide the probe through it to have it resting in the water, take some epoxy or putty and seal the lid so that no heat seeps out. I would only say to do that if you plan on cooking beer cooler sous vide on a semi-regular basis. With this method you can just add some hot water when it goes below 150.
Let the ribs cook a minimum of 12 hours up to 24 hours this way to make sure the meat gets tender. When you are ready to finish and serve the ribs, heat your grill to high heat, or turn on your oven's broiler to preheat. Let it get as hot as it can. Place the gril/broiler rack as close as you can to the source of heat. Put the ribs on the grill, or under the broiler (if using the oven, place a pan under it to catch the drippings), and let them sear for 30 seconds to a minute per side, enough time to give them the brown color, or maillard reaction, of caramelizing for both the visual, and taste appeal. Coat with your favorite sauce and dig in.