Where can I get me some of them there juicy worms?

The current TV propaganda for the Olympic equestrian events in Hong Kong proudly informs us that 60 million earthworms are at work keeping the venue green. I'd like to get hold of some of those.

No, seriously, no kidding. After weeks of heavy rain, my little patch of garden in Taipo is a horrible mass of compacted heavy clay, where I've never seen a single worm since moving in five years ago. I reckon a few thousand earthworms would make a big improvement to the soil, but where do I find them? I don't suppose digging up the Olympic venue would make me very popular, but if the government can get hold of 60 million of the critters, there must be somewhere here that sells them. Anyone know where?