Interesting seeing these home made attachments. If people would say a bit about how their gizmo is made / how it works / how to use it we could end up with a very useful tutorial
I was going to make a full writeup, but for the sake of this thread here is a bit more info;
My macro flash diffuser is made from card, ducttape, velcro, metal foil and Lee spun diffuser filter. I designed it to fit my SB600 and to diffuse the light as much as possible, while bringing it down as close as possible to the subject while using my Signma 150mm without getting in the way. I also designed the end to point down slightly, so the light would come down on the subject (simulating natural light) if the flash was pointing forwards, but could be pointed forwards by angling the flash up.
To make it I measured the size of the flash, and made a card 'collar' that had a tight friction fit. I then measured and cut 4 sides from card. These shaped so the front surface is as large as practically possible. I then covered the inside of the card with silver metal foil so as to reflect the light as much as possible. The sides were then ductaped to the collar and covered in ductape so as to make them stronger and water resistant. The front is made from a card 'frame' with Lee spun light diffuser sheet covering the front of the frame. I decided on the spun diffuser as it provides a decent amount of diffusion and isn't quite even so would provide a more natural lighting. All 4 side are hinged on the collar, and joined together with velcro. this allows me to remove the front and collapse the diffuser flat, so it fits nicely in my bag.
For mk2 of my diffuser I am going to try and make it out of light, thin and flexible plastic to make the whole thing lighter. Although perfectly usable, it does pull a little on the flash. I would also try and get hold of either silver spray pain, but self adhesive metal foil, rather than relying on taping the foil down. I would also like to make multiple diffuser filters for it, so I can cnage the light effect as and when needed.