The 'hook turn' is a strange traffic manoeuvre which appears to be localised to only the city of Melbourne, Australia.
It's completely official and means 'right turn from the left lane'. This may seem suicidal at first, but once you hear the explanation of its workings, you'll undoubtedly say, 'That's not suicidal - just dumb.'
The hook turn works something like this:
You approach the intersection wishing to perform a right-hand turn. You see that little sign hanging from the overhead power lines that says 'Hook Turn'.
You swear for a few seconds, then you move into the left lane1.
You sit just in the intersection on the left, safe in the knowledge that no cars are coming from the right to hit you, as they've got the red light. And if one did come at you, just out of spite, he/she would meet the stream of cars that are shooting past you on your right.
You edge up to the 'big asphalt square of death' so, assuming you're the lead car, you're positioned facing forward, and to your left are a pack of angry city drivers waiting to plough right through you when their light turns green.
The idea is that when it does turn green, all the cars shooting past you will be gone, so you can hang a really hard right and peel out, with all those angry city drivers in your dust. And you're alive!
Usually the worst that can happen will be a lot of honking, then you take off with those drivers right behind you.
No-one knows why this procedure is necessary.