This is a page from the notebook of Scott Murphy, including Pens (the deadliest office supplies), the Penny is mightier than the mugger, Surveillance on a budget, and homemade brass knuckles:
* Keys are wonderful inventions. The more the merrier. I prefer four per keyring—that way, should you get into a tight corner, you can wrap your hand around the keyring, each key coming out between the fingers of your fist. They make for some nice brass knuckles. They will hurt to use them, but I can guarantee that they will hurt the other guy more. Also, if you are dealing with only one person, key make for a nice, shiny distraction when you throw them at your attacker's face, and plant a solid kick between his keys.
* Wifi cameras are great in terms of surveillance—when you want to break in. Call in a bomb scare at the building next door; the bomb squad's signal jammers will stop all cell phones, remote control bomb detonators, and the wireless linkup of the camera.
* Always carry AT LEAST one good solid pen with you. A silver-colored, metal pen works best: holding it like a knife can work well for you in a dark alley, filled with bad lighting —the average thug sees something bright and shiny, moving quickly, they will hesitate for seconds, which is usually all you need to get the hell away, or follow up with an attack. Holding an average pen in the middle, with both ends sticking out of your fist, works if you're well acquainted with pressure points; jamming it into the inside of someone's wrist (about an inch down along the forearm) will cause their fingers to pop open, and ramming it behind their ear or into their temple will at least give them a bad headache, if not disorient and/or knock them out.
* Metal pen (ONLY), holding it a like a knife: for instant kills, stab it into, and through: right behind the ear, into the ear itself, under the chin (through the tongue), into the throat (all sorts of good things there), the eye, or through the temple (if you can generate enough force). With a sturdy fountain pen, you can stab someone in the kidneys, but I wouldn't rely on it a second time, and you'll probably never write with it again.
* When you're feeling lazy about surveillance, or when your target is wary about someone sitting in a parked car outside of their house, a web camera with a wifi hookup can work well for you. They're cheap, reliable, hard to spot, and they'll stay in place if you use dental putty to anchor it. Webcameras also come with night vision; it's more expensive, but worth it.
* Simply, keep your cash in a money clip, even a sturdy paperclip will do. And at least keep some cash on you in that fashion even if it’s just a bunch of fives and a few singles. For preference sake, keep the money clip in order of denomination, with the smallest dollar bills on the outside—from anyone’s point of view, it looks like a collection of dollar bills. However, when someone comes up to you on the street and asks for your money, they’re more likely to take into account your clothing and your body posture than money.
With the money clip, you just hold it up, and make sure their attention is firmly focused on it, then you hurl it to the side, and run in the opposite direction while they eyes follow the money. Most muggers are just thieves, and are most likely to just take the money and run. They’d really much rather not have a felony murder charge in the making... unless they're aiming for a Darwin Award, then all bets are off.
A similar variation works for just plain running. If you’re the kind that throws away pennies, hold onto them, they can work to your advantage if you keep them in one pocket… take a collection of them in your hand while you’re “searching” for your money, then hurl it straight up, into your assailant’s eyes, making him cover up. If you’re interested in running, you can add a sharp kick to the groin or solar plexus for good measure. Or, if you want to put him down, you can use it as a distraction while you beat the hell out of him—if you have some idea of what you're doing. If not, I suggest running.
* When escaping from a room when the hallway is flooded with security, or other unfriendlies, go through the subceiling, since vents are too small unless you're a six-year old..