Mythbusters is my favorite show. They learned alot from that boiler explosion, they learned that they could make a boiler with a water heater.
Mythbusters utilised this idea in the steam machine gun episode,
[ame]http://youtube.com/watch?v=YKhLgPyymfU[/ame]
I like and dislike this idea, it has an atvantage of being cheap and easy. But can be deadly like in the video you showed.