Teenagers - How do they spend their time?

I am new to blogging and I'm sure nobody has seen or is even looking for my blogs but I want to throw a question out there. What do your teenagers do on the weekends? I have two step-children, one is 12 and in 7th grade and the other is 13 and in the 8th grade. They come to our house every other weekend plus some days during the week and although, we are busy with dinner, showers, homework, etc. on the weeknights, we struggle with the weekends. If they are lucky enough to have not had their cell phones taken by their mother, they sit around and text people all day and night. If they don't have their phones, they sit around and do nothing. Neither of them seem to have any interests, they don't go over to friend's houses and they don't invite friend's to our house. I should mention that their other house is not far and many of the middle school aged kids in our neighborhood attend their school. With two preschoolers too, it is difficult to always be out trying to find things to do that will appeal to all age groups. Plus, it is somewhat stressful to feel like we "need" to entertain everyone all weekend long. So, I ask again, what do your kids do? Are there places where middle school aged kids go? When I was that age, we went rollerskating, ice skating, bowling, to the movies, and to the mall. Is it just our kids or do kids just not hang out together anymore? I'll take any suggestions, comments, or recommendations.