OK, saw this sub-forum and felt this had to posted in here somewhere! One of my favorite short stories...
https://www.multivax.com/last_question.html
OT: After trying pretty much every flavor and type light available over the years as a dedicated weapon light, I've gravitated to using Arisaka bodies (essentially a Surefire body, but with built in mounts vs adapters) and Malkoff head units. I typically use a genuine Surefire tail unit depending on the application, but there are literally dozens of options out there to fit a particular need.
Arisaka makes a lot of cool adapters and mounts for a huge variety of different applications, but the illumination home page is here: https://arisakadefense.com/illumination/
Malkoff home page here: https://malkoffdevices.com/
This combination gets me what is essentially a Surefire professional/duty rated light at less than 1/2 the price, and frankly is a better (ceratinly lighter) product IMHO. Bonus: both offer military discounts if you served... makes a good deal even better!