Workout needs more fun?

School is ending and I need a better workout! I am on the leaner side but my family is all obese and if I don't work out I end up gaining weight! In school I have 3 gym periods a week (2 hrs and 15 minutes) and we almost always play sports and I love it! It helps me relieve stress and be aggressive and workout and have fun! On the days I don't have gym and one day on the weekend I work out (usually only and hour at max to stay healthy). I usually run on the tread mill but that gets really boring! I watch tv but that doesn't tend to satisfy me. If i try listening to music I love music so much i try to sing along but I get to out of breath and I have to stop and slow my work out down. Over the summer there is no sports team to do because the only way to join is to join in the beginning of the season (October) (I've tried but you can't this time of year). I also have a pool, but it gets boring to, swimming back and forth.I would love to have my friends come over and play sports but in the summer they get lazy because of the intense heat. Can anyone help me?