Time to borrow your favourite nephew again... Find something heavy, lift it overhead, then throw it as far as you can!
-You will need to find something heavy. Heavy enough that you need to concentrate and struggle a bit but light enough that you can lift it safely. Big rocks, logs, kettlebells, medicine balls, your 5 year old nephew... anything will do as long as it's appropriate to lift and throw it.
-Regardless of how you lift it, keep your back straight and use your glutes, hamstrings and quads to do the work. A traditional clean and press may work best. Once you get it to chest height, push it overhead and bring it back down to the chest before launching it as far as you can.