A hobby is one of those things that you put together with pop-sicle sticks, right?
Computing
I don't know why I'm so drawn towards computing/computers in general, but I
know that the reliability of the only os that has weathered 25 years of computing draws
me to UNIX and UNIX-like operating systems. In the technical field of computing,
free is better, because it legally restricts less, allows answering 'how did they do that?',
and in general costs less.