People have the weirdest hobbies. Have a look at this guy: http://www.themysteryworld.com/2011/02/tatara-project-guy-ma...

Making knives starting from the very scratch (that is, making their own steel to start with)

This looks like the original: http://www.arscives.com/bladesign/tamahagane/main.htm

Also has additional information on it.

And actually, if hacking with computers wasn't so common, it would be perceived as quite awesome, too.

I'm sure you'd like to think so, but unless you have a blast furnace in your garage you're not as cool as this guy, sorry.

How about a CNC mill, laser cutter or reprap? :-)

Yes, unfortunately.

Fascinating article, thanks.

A friend of mine is 'bio hacker'; he works with different microbiological organisms to learn about them and build better ones with specific traits. This article describes it better than I can: http://www.nature.com/news/2010/101006/full/467650a.html

I am a biohacker too, actually. I just submitted a paper on how to build a Drosophila lab with little budget, for schools or biology lovers.

Cool, do you have a link I can share or something? Sounds fascinating.

As soon as the paper is accepted I will write more here on HN. Cannot do much before as for editorial requirements, sorry.

I'm an amateur bladesmith. This guy posts regularly on one of the forums I participate in. He's chronicled his research there in very accessible, but rich detail. Really brilliant stuff (from my layman perspective).

link?