A common complaint at all types of concerts, shows and films is that the sound is not good. Usually this is because of the acoustics of the room and the position that the listener is located. Why not feed the sound system into a Wifi router so that anyone with a wifi enabled device eg smart phone, can just plug in their headphones and enjoy good quality sound. The easiest way would probably be to provide a free service but I guess you could have some system whereby a charge is made onto the users phone bill so that it becomes a profitable service. Further developments could include the ability to turn the speech channel on films up or down or alter the balance in other ways. It would give BT a good presence and enable them to be associated with a more up to date image.
Another option might be to provide streaming video images but in some respects this is usually covered by the placement of large screens although not always the case in smaller venues.