I built a copy of the dreamachine once - I had a Re/Search book about Burroughs, Gyson, etc, and there were lots of pictures, possibly there were even measurements, I don't recall. Anyways, I just got some thick paper and cut out the holes, the hardest part was finding a working record player that did 78 in the late 90s. It wasn't nothing, but it also wasn't much.

I also remember trying out a more fun device at the third Lollapalooze where you lay with your face to the sun and the thing fit over your face like a snorkel mask, with a little plastic tube you blew into and which spun a thingy and did the same effect. What was neat about that one was that you could control the intensity of the visuals by blowing harder or softer, by tilting your head for more or less light, etc - more interaction makes better fun.

A more capable than me friend even had a go at an electronic version with LEDs, but it was also more boring. I wish I had bought the snorkel mask.