The new worm farm is made from two cheap 50 litre fish bins with lids. I've drilled a bunch of ~6mm holes in the bottom of each bin (for the worms to crawl through), and a series of ~1mm holes around the top rim of each bin (for ventilation).
I've also drilled about twenty ~1mm holes through one of the lids, also for ventilation. The un-drilled lid will be used as a tray to collect any liquid that seeps out from the bottom bin. That liquid is full of good stuff for the garden.
Worms don't like light, so it's important that the bins and lids are not transparent.