The latest is a Maskery pattern dust extractor:
and yes, I could have made it out of 40 mm pipe and brackets, but that would have involved going to a shop, and where's the fun in that?

The three brackets each have two very strong 20 mm diameter, 6 mm deep magnets glued into the back face (which is curved to match the shape of the door: a 1.5 metre radius curve!)
The bottom piece (printed in black) is shaped at the end to match all the other bits and pieces in my garage (actually based on the outside diameter of the tools that came with vacuum cleaner, so I can still use those without disconnecting the dust box).
Close-up of the top bit to show how it works for those too lazy to watch Steve's video (the sawdust you can see on the underside of the table was there before I fitted the dust catcher):
I was far too lazy to do as thorough a test as Steve did in his video, but I thought it was worth resawing a bit of 150 mm poplar in half and seeing what happened:
Not perfect, but pretty darn good: