May i ask what do you mean with FE exchanges? I have totally no idea :S
Hi and welcome to the DISBoards!
An FE exchange is a gift exchange that folks here on the DISBoards do with each other on their cruises. The FE stands for Fish Extender. On the Magic and the Wonder their are brass fish which are in front of every cabin that the cruiseline uses to give you messages, etc. Folks make pockets to hang from their "Fish" to allow the gifts to be left easily.
Think of it like trick or treating without the trick or secret santa without the secret (since it seems that a lot of folks sign their gifts - which I think is a very good idea so I will know who to thank for what

.
If you have already booked a cruise check out the Cruise Meets thread at the top of the page and find the thread for your group so that you can join the fun.
For the OP... As for what to give teen boys, I am in the same boat... literally

since we are on the same sail date as you know. I am struggling as well, because folks can be all over the map regarding their interests and what they think is "cool". I have heard that some folks give arcade cards but I don't know how much that would cost and that really isn't a keepable gift.
I like the sunglasses idea (you can sometimes find them at the 99 cent store or even Big Lots for a decent price). Hmm, what about something from Minnesota? What is your area know for - I confess that the only thing that springs to mind for me is the Minnesota Vikings football team but I am pretty ignorant about areas I don't reside in.
Ooooo... I just got an idea... What about a cool keychain from your home area for those kids who are 15 and up since most of them are chaffing at the bit to be able to drive.
Oh, and I can personally vouch for Aero Bars and Crunchies as well. Years ago I used to manage a British Imports store and I managed to get addicted to them. They are really yummy and we don't really have anything comparable here in the States.
I shall now return this thread to its rightful owner...
Take care all, help lots of people and have a "Wonder"ful day!
Tisza