Any ideas of team building games for teens?

You'll need a tent for this one.

Tell the group there's been a chemical attack that's left all of them feeling scared, so they have to hold hands in a big circle and can't let go.

It's also left all of them except one totally speechless.

Put the tent in the middle of the circle and tell them they have to erect it without letting go of each others hands and with only the one nominated person speaking.

I've played this, it was fun!

have a dependancy game where you give each one of them a fake injury or complication like :

a broken leg by tying a stick to their leg so they can't bend it, same thing with an arm.

blind or can't see in one eye with eye patch or bandana. Tie two of them together.

Give them tasks to do like building a fire, making their dinner, getting the whole group around an obstacle. They will learn to depend on each other for help.

Depending on your budget take them to a high ropes course where they repel and climb. Rent a sailboat with instructors and have them learn to sail the boat together. Have them do a service project like repaint a needy persons house or do their gardening. Have them work at a soup kitchen.