Mellotronists

As one who has worked with lasers for many years, you'd be amazed at what 
the general public thinks are lasers - combine a mirror ball and a fog 
machine, and people will argue for hours that it is a laser show.  Even the 
small moving-pattern disco spots that many clubs use are perceived as lasers 
by many.  Sad how scientifically illiterate the average person is.  And, 
almost any large laser is water-cooled - they develop a tremendous amount of 
heat.  We actually had to run hoses from the nearest bathroom into the 
planetarium to host an OmniScan (full-dome laser projector) demo a few years 
ago.