Happy Birthday, Mr Laser, Happy Birthday ... to ... you
Today, is, according to google, the anniversary of the invention of the laser. First demonstrated in 1960, it was known as a solution looking for a problem - everybody agreed it was clever, but it took some time before it saw a practical use. Now, every single "western" home has at least a handful of lasers, ad they have seen duty everywhere from art to war, via medicine and astronomy.
Time to have a quick review of how this tricksie piece of hardware (especially the LED variety) has been treated by our members:
Laser vortex from this Instructable
Google's laser results