This is an angle on gangs and guns, asking what belonging is and how we can truly belong
Start with the famous game where you have 6 volunteers and get one of them to go outside the room briefly. The others are primed to answer a fairly easy question wrongly deliberately. So make sure the one who goes out is quite a strong character!
So the question may be 'Who is the American President?' and each one of them has to answer 'Leonardo di Caprio' or something. Or, 'who is the Prince of Wales?' They answer Prince William (it's Prince Charles by the way). You then bring the other person back in and ask the question (maybe do it 2 or 3 times to build the pressure) and see the peer group pressure work so person 6 answers wrongly (hopefully!)
Either way, you'll manage to get the point that most people like to belong!
Hands up or not. Who has ever belonged to a gang? What about a street gang? Maybe you've got a personal story to tell about this, maybe Cross & Switchblade type story. My story is that I belonged to a gang of football hooligans and it gave me an identity, something to belong to. I also belonged to the underground rave and party scene. We were different and were doing drugs. That gave me an identity.
What I found out was that the buzz was there for a bit but it went. I could go to a rave, buy some new cool clothes, go to a footie game and drink with the lads but the buzz went away and at the end of the day I was usually more empty than before because my expectations of belonging weren't really fulfilled. Some of the guys I was with were drug dealers and very dangerous characters who didn't really give a monkeys about me. The only time I found I began to have real value was after my brother was killed in a car crash and I decided I had to give my life to Jesus. This totally changed me. Now I want to spread the message of Jesus - of his love and hope and change for you!
Another good book to read and then take bits from is the story of the ex-Bristol Rovers hardcore hooligan - 'Heart of a Hooligan', written by Paul Alkazraji about how David Jeal turned away from hooliganism to God after witnessing a brutal attack on a Swedish youth by English hooligans. It's a brilliant book.
Update (April 2013)
BBC Video of Dave Jeal - http://www.bbc.co.uk/sport/0/football/22079178
There is also a group in Handsworth, Birmingham called 'Men To Men Mission' from Pilgrim Church in Heathfield Road - or a group of women called, 'Mothers Against Violence' based in Manchester with great resources on gangs and a community / Christian response.
Even better, get someone cool in to school to do their testimony - someone good up-front and with young people.
Maybe for you, belonging isn't about bad stuff, it's about being popular, being seen as cool, or maybe being seen as different. Maybe your image is deliberately different so you really stand out. At one school in Exeter a lad was very visibly a gothic and because of this was beaten up very badly in school, hospitalized and had to change school for his own safety. This kind of ignorance is what happens in gangs and often between nations when they fight each other.
SO WHAT MAKES PEOPLE BELONG?
Maybe ask for answers but better to have some prepared already - maybe on OHP, laptop, big bits of card (and even get people to come up and hold them up if appropriate! They probably won't want to!)
Clothes, Music, Football Teams, Nationality, Family, Where you live, Job, School or College, Colour of skin, Ability, Looks etc.
FROM THE MOVIES
In the movie Spider-Man, Peter Parker is a geek in school and longs to be different. One day he gets super powers and in school is able to give his bully a good kicking. Even then, however, people still describe him as being a freak. Show the movie clip if you can with a big TV.
The point is that we can think we belong, we can belong but this is only temporary. Clothes change, people change, you leave school, you move away, you get new mates, get married, get new priorities.
There are loads of options now, you don't have to belong to something that's bad and messed with your head. You could even ask people like me or your teachers for something positive you think is needed in school or in your area to make a difference.
Whatever, as Christians we believe the one thing that doesn't change is God's love for you. God wants everyone to belong to him. He accepts you as you are unlike other people, even if you don't believe it, it's true!