Not exactly a sick joke, but...
This was told to me by a friend, who couldn't quite remember how it went, and now I can't remember how he told it to me either, so I'll have to make most of it up.

Anyway, there's an Englishman, an Irishman and a Chinaman, and it's the morning of their first day working on this building site. The gaffer is trying to decide where to put each of them, so he says, "Do any of you have any experience operating a crane?". The Englishman raises his hand, so the foreman says, "Right, I think we'll start you off on the crane, then". He turns to the Irishman and the Chinaman, "Either of you any good at building walls?". "Why, I'm a dab hand at brick-layin', so I am", says the Irishman, and off he goes. Now he has to decide where to put the Chinaman. "You look like a pretty smart fella actually, so I think I'll put you in charge of supplies".

Later in the day, the gaffer spots the Englishman and the Irishman taking their tea-break, and he goes over to speak to them. "You're doing a grand job so far lads - listen, have either of you seen the Chinaman? I've been looking for him all day". They both shake their heads, so he heads off back to his office. Just as he's getting there, the Chinaman leaps out from behind a big pile of sand and yells, "SUPPLIES!!!"
(disaffected, Mon 13 Sep 2004, 13:23, Reply)