Hiya
I'm going to the HV in a few weeks and have been to Sharm twice before (not the HV). My kids are also teens.
First Choice seem to offer most of the trips, but I think they come under the Thomson umbrella now. Thomson were one of the first people to take folk to Sharm in large numbers so they have probably got their act together in terms of what trips they offer. If you want to go with a local company people seem to recommed Fayed Travel so they might be the ones to compare FC's prices with.
You maybe best going to the welcome meeting taking all the bumph and then going into NB and checking out the local companys, I am sure they will be cheaper. HV is approx 25 mins in a minibus from NB.
The other things that seem popular with teens are quads and there is a trip in the dessert star gazing. In the summer months First Choice used to offer a sunset dinner cruise. They may wish to snorkel as well and there are organised trips for this to Ras Mohammed and Tiran Island.
Not having been yet I am not too sure what is in the immediate vicinity of the hotel, although I understand that there are now shops, a mall, various restaurants and bars at Nabq which should give somewhere to go in the evening for a change of scene without having to keep going into NB.
You need to read the visa sticky as if you are going to Luxor, it will be best to get it on arrival.
HTH, Doe