We all have things that get to us; we all get annoyed with other people or issues, some that we simply cannot let go of.
Have a reflective time where your young people can think through anything they feel they should 'let go' of. Do they need to forgive any one? Is there something that annoys them regularly? Is there a jealousy, a longing in their life that they wish did not control them any more? Encourage them to write these down and to pray about them, for God to inspire them to actively change their attitude.
Ask them to come up with an action plan - what practical things can they do to help them let these things go? Follow this with a 'burning time'. If you are inside, light a fire in a metal bin to throw the 'let go' paper into. If you are outside light a bonfire and burn them there. Send them away with their action plans.
Have a discussion time on sin and how we are made new by Christ's sacrifice (Colossians 1:21-23, 3:1-17). Focus on verse 3: 'For you died and your life is now hidden with Christ in God'. Plant some seeds or bulbs (any will do, depending on the season. Crocuses are good for coming up through the snow in winter, cress is a quick one for those who are impatient.)
Make the analogy of burying what is ugly and sinful and which isn't useful for God.
Now they are hidden, but remind them that at the right time, and with love, light and water, the seeds/bulbs will take root, change and grow in to plants that are useful and beautiful. It's all about burying the old and becoming new.
Find a large cardboard box. Put in it: a Bible, a candle, a loaf of bread, a drink, and a piece of rope. Take your group on a walk; it can be from someone's house to your usual meeting place, or a country walk to the top of a hill, or you could create a specifically difficult route that is complicated and hard work. The challenge is: the group has to carry the box to the end location. At no time must the box be put down. Every member must have a turn at helping to carry it and the box must always have at least two people helping to carry it.
At the end ask them to sit in a circle and open the box. Discuss the objects. Ask one of them to find Acts 2:42 in the bible and to read it out. This is a list of the different aspects that made up church life when Peter met with the first Christians. Explain that the objects in the box are symbols of aspects of church and by carrying the box it shows how we should carry one another's burdens within the church - even when you come across rough ground.
The Bible is the word, the bread and drink symbolise the recognition of Christ's sacrifice, the candle symbolises prayer, and the rope symbolises being 'tied together' in the fellowship.