Who can tell me what this does?

[iago]

Code:
while (1) {
  fork();
}

Can I do it yet? =)

That's basically what it does, but how?

He won't know unless he can find the log of me explaining it to him last night ;P

Haha, I didn't think he'd figure that out himself :)

To quote somebody else:

The ':()' defines a fuction ':' with a fuction body of
{
: | : &
}

As you can see this is a recursive call as the fuction ':' is called,
it's output passed via a pipe as input to the fuction ':' and this
whole command is run in the background '&' .

The last ':' in the string (after the ';') calls the fuction and therefore
starts it all of.

(Krazed edit: Disabled smileys.)