First of all I happen to be in my twenties and a male. But for mothers and fathers well in there fifties you could say they may have lost touch with "trends." So from my perspective here's some things teens have been raving about this year!
Any form of touch screen tablet. I phone, Blackberry, etc.
Any sort of data or social phone. Teenagers seem to find life impossible without them these days.
A gift card to the movies. 50$ could be an appropriate price for some popcorn and drinks and a movie, and still gives them enough money to take a sidekick or a date along.
Cologne. Now you may think they're too young for some cologne if they're in their teens but hey; B.O. is at its worst and that won't help them attract the opposite sex. Which lets face it, seems like a top priority for teens.
A pack of cigarettes! Just kidding..
Wallets, shavers, after shave, watches. anything they'll need in their future years is always a good idea.
Video games. careful with this one. If your going to buy your son a video game for Christmas, the first red rule is find out the name of the system they own first. Then find out if the game is compatible.
The hottest video games out right now are Battlefield 4, Call of Duty: Ghost and Grand Theft Auto V to name a few. Any 2014 sport game depending on their favorite sport is also a classy idea.
Anyways good luck shopping and have a Merry upcoming Christmas!!
Hope they enjoy their gifts and if you have any questions feel free to comment below.