im a 16 year old high school senoir tipping the scale at 240 (235 now) im 6'2 and having the time of my life exercising. ( not realy) well if you have any ideas on what excersises i can do to better myself please tell me im currently using a treadmill and an ab lounge.

You should add more weights. Try doing 2-3 sets of 8-10 exercises for each of the major parts on your body at least twice a week (arms, back, legs, etc.)

check out the thread on HIIT
http://www.traineo.com/12_1436_0.html

also check out this site about a good lifting routine:
http://getbig.com/articles/faq-dav1.htm

the best thing you could do is join a sport. you'll make friends, get a great workout, and build some character. sports look good on college/job applications too.

it's a lot easier to get in shape when you're having fun and getting a lot of encouragement.

oops, might i suggest lacrosse? hehe, personal bias.