The Bamboo Rocket Festival takes place in Thailand every year. People consider building rockets to be a hobby there. For all I know, there are people building these things here in the US too. In fact, I'm 100% positive there are people doing this here. I just hope I don't live next to one of them.

This first rocket is incredible. It doesn't look like your traditional rocket, but it flies like crazy:

 

Then, there are the less successful attempts, which might be more fun: