Prep the ribs:
On the back of the ribs will be a very thin but very tough membrane that you must remove. You can't really see it well, but trust me that it's there. I usually use a knife to pry up a corner of the membrane, then I just pull it down the entire length of the ribs. Sometimes it tears and you have to try a few times, but you definitely don't want to skip this step unless you want to deal with the membrane while you're EATING. Once the membrane is removed, put the dry rub all over the ribs (both sides) and rub it in. The meat will take on some of the colors in the dry rub and look a little reddish.
Wrap the ribs in some heavy duty tin foil and let them hang out in the fridge til you're ready to cook them.
Cook the ribs: At 250 degrees, place the ribs wrapped securely in tin foil onto a cookie sheet (sometimes juice/fat can escape the tin foil) and place them in the oven. cook for 2 hours.
After 2 hours, pull them out and open the tin foil to take a look. At this point you can add a little apple juice on top of them, but that's not really necessary.
Re-wrap them, and put them back in for another 1/2 hour.
Pull them out again and open the tin foil completely. At this point you can brush some BBQ sauce on them, or leave them the way they are.
Crank up the heat to 350 and put the ribs back in the oven with the tin foil open. After half an hour, they're done! You can always do this last part on a BBQ, but watch the ribs and make sure they don't burn from the sugar.