SysRq

For those who are too lazy to look at their keyboard to find the button

“System request (often abbreviated SysRq or Sys Req) is a key on keyboards for PCs that has no standard use.”

~ Wikipedia

The SysRq button is a mysterious button located on many keyboards, designed to confuse, confuddle, irritate and genuinely piss-off the user of the keyboard. No known use for it has yet been discovered, despite its presence on nearly every keyboard in the world. Some say it has something to do with raising elephants being so utterly boring. However it has been known to cause such a thing as amusement when forcibly ripped off the keyboard, and super glued to your sleeping friend's forehead.

Origins

This could be your friend!

The SysRq button originated in the Great Keyboard Depression of 1995. Keyboard sales were dropping, and so the manufacturers of keyboards needed a cruel,evil and cheap hoax to get people to buy more. After testing and deliberating, and much stabbing of random buttons, the SysRq button was born, aggravating the user of the keyboard enough to destroy their keyboards and buy new ones. This ended the keyboard depression, however it also pretty much pissed everybody off.

Rumors

• Many people believe that the SysRq button and the Print Screen button are actually the same key. This is utter nonsense. They are clearly different keys. The Print Screen key is the one located directly above the SysRq button. You should be able to locate it on the below diagram map. If you are unable to do so then you obviously suck at keyboards and I hope you are typing with some other device (Such as a stapler, or pencil sharpener).
• Some believe that SysRq is two words, abreviated, like- however, these rumors have been shown to be completed false, as evidenced in the Logitec 2200d Keyboard Users Manual (2004) which clearly states 'SysRq is a single word, you goobers' (page 34, immediately below the bold-type line 'Press Alt-F4 repeatedly to fix your computer').
• SysRq was believed (upon its conception) to end processes running on the Operating System's main thread, due to its being the most 'complicated' key on the keyboard- and this explanation being the only one corporate IT departments could come up with for its existence. However- if you believe anything IT tells you, you've more problems than them (egads!).
• The CIA caused the fiasco known as 'The Bay of Pigs' by inadvertently holding down the SysRq key for the duration of the mission.
• The SysRq button was added by Indian electrical technicians to confuse users of English QWERTY keyboards, as a social protest of outsourcing, before realizing there-in lay the source of their income.
• Another (although far less prevalent) rumor is that the button is synonymous to the Break button (which is also rumored to be the same as the Pause button), but designers could not bear to remove buttons from the keyboard, so kept them- just in case some bit of software made use of one (but not the other) key(s).
• Recent data suggests that the SysRq may be an ancient artifact left over from PeeEstoo dynasty. Its current location on the bottom half of the key is evidence of it sinking further and further into your keyboard because of its disuse and very old age (like dinosaur bones are in the ground, for idiots that don't understand.) Experts say that it will continue push to deeper into the keyboards crust and no longer be visible by 2030.