Incentive: 2 days
The trebuchet is an ancient siege weapon, similar in function to a catapult or ballista – all designed for propelling heavy stones, pots of burning oil, dead animals and other objects at the enemy, usually over walls.
The main characteristic of the trebuchet is the use of principle of gravity, i.e., the energy for a shot is taken from the energy of the gravitational field of the Earth. Practically, it means that the construction of the trebuchet is not that complicated and does not require any special materials or tools; we just need wooden poles (or sticks), and the rope for binding. That's it! That is exactly how it worked in medieval times, during the siege of the fortresses. They did not carry around huge, heavy weapons; they simply built them on the spot from anything they could find.
To build a trebuchet one needs to know the proportions that will make it functional – its height up to the bar, boom (arm) length and the weight of the counterweight. An experienced instructor will advise the team about the optimal proportions. The bigger the trebuchet is, the heavier the load (weight) it can cast. For example, if you build a small trebuchet that is 1.5 meter high, it can cast a load of about 0.5 kg (half-liter bottle of water) up to 30 meters long.
Thus, a trebuchet can be built on the spot in a relatively short time from available materials. When the trebuchet is ready the contest can take place – a distance and accuracy (target) competition between the teams. Despite the seeming awkwardness of its construction, the trebuchet can be quite a precise weapon, e.g., from a distance of 30-50 meters you can hit a circle one meter in diameter.
In addition to the medieval trebuchet, archery and crossbow target shooting seem to be a good match. It might also be interesting to compete in throwing spears, special short spears and axes. There can be a special arena set up for shooting burning arrows at straw targets like in Robin Hood movies.