Back in our adventurous youth, my brother made an interesting discovery.
Take a 4-gallon oil drum with the top cut out, as used by all the best workshops as a rubbish bin.
Invert this drum on a flat piece of lawn.
Stick the end of the oxy torch under the open end and turn on an oxygen-rich gas mix for about ten seconds.
Withdraw the torch and light it, then play the flame over the lower side of the inverted, gas-filled drum.
Shortly thereafter, the drum will leap about fifty feet into the air, accompanied by a VERY satisfying BANG,
It will then fall to earth with a CLANG, hopefully not onto the giggling idiots who just launched it.
In a suburban back yard, the din is impressive and the need for level ground imperative if you don't want to land the drum over the fence into the neighbour's washing, or on your own roof, cars, mum's flower-beds, etc...
The price of welding gas these days makes such fun and games a bit less attractive.