Back in the day, I played bass in what could be construed as a "hair band" and we "needed" a fog machine - so I made one. This was before liquid fog juice and all that DJ crapola
The whole thing was based around a 5 gallon metal bucket. The lid had a squirrel-cage blower mounted and sealed with RTV silicone. The outlet of the blower was connected to a length of flexible hose (from an old vacuum cleaner) and run behind the drummer...
There was a small "intake/feed" tube at one edge, I think I used 2" PVC pipe. This extended down to about half way from the bottom of the bucket.
A stainless steel livestock water heater element (500W??) passed through the side of the bucket (more RTV) and was used to heat about 1-2 gallons of water to something around 150 degrees F.
To use it, you pre-heated the water, then dropped chunks of dry ice into the intake tube, covered it, and then turned on the blower. Out rushed huge volumes of clean, dry ice fog. We got the dry ice from the ice cream shop, where some really cute groupie-types worked (yeah, we made some new friends alright).
And yep - I had a ~6mW HeNe and a crude speaker-cone/mirror "scanner" that was connected to a small practice amp through the mixing console to my bass guitar input channel (hey, it WAS my laser and fog machine after all) and I'll tell you what, it was really, really cool. Quite the crowd pleaser. A friend acted as the techie/roadie and operated all this great stuff from behind the scenes.
Man I would have killed to have even a 1mW greenie back then! A "GreeNe" (green helium neon), HeCd or Argon laser was just way out of reach...
/reminisce