How
stuff works is a free collection of articles explaining how different things in
real life work. For example, there are articles on how
MP3 works, how
helicopters work, how
horses work, how
cruise missiles work, how your
teeth work and lots of other stuff. It is all well-explained and
illustrated (no
pr0n, though). The author is a guy who calls himself "Marshall Brain". That seems to be his real name, actually. He also tells juveniles not to have sex, which is
dangerous. But other than that, he's a
nice guy.
HSW is at <www.howstuffworks.com>. Duh.
Cf.: How Things Work: <http://rabi.phys.virginia.edu/HTW/>