Check out Will Luo‘s sweet 3rd-generation homemade pinholga floppy disc shutter. He writes:
the third incarnation of the pinholga’s shutter. i got the idea of using a floppy disk from this blog entry. this one is customized for the holga though. it was much easier and faster to make than the last version:
1. cut off the part of the disk that has the spring-loaded protector. the disk i got had some soft paper coating inside which i removed as well.
2. make a small cut here and bend the corner up to make a small "handle" that can be used to push the floppy door open. i glued a little piece of foam there to make it less slippery for the cable release…
Continue reading at Luo’s Flickr photostream.