So back when I was fresh outta college, and Windows 3.11 was king, I decided to mess with the salesguy the engineering team worked with. Windows let you hook i

So back when I was fresh outta college, and Windows 3.11 was king, I decided to mess with the salesguy the engineering team worked with. Windows let you hook into the global message queue and intercept/modify stuff. Windows was cool in that you could modify the message args passed, and your new values would be sent to the other windows in the message chain. Making sure you were in the global message queue ensured you got the message first. So I basically intercepted every WM_MOUSEMOVE message (which is sent to windows every time the mouse moves). The arguments are the X and Y position of the mouse. Of course, I do the following: xPos += 4 * rand() / RANDMAX - 2; yPos += 4 * rand() / RANDMAX - 2; Which would cause the mouse to behave "jittery" -- made it harder steer the mouse or land on a button you wanted to click. The trick was to make it difficult to use, but not impossible. Just really annoying. Especially when you were trying to concentrate. After about a month or so one of the IT guys I knew stopped by my desk, and asked me if I knew anything about this. He knew me personally, and knew the reputation of the engineering team, and figured we might have had something to do with this. I promptly went to the salesguy's computer, and held down three keys on the keyboard corresponding to the three initials of my name. The problem instantly vanished. Apparently IT had replaced his mouse 3 times before they suspected it might be a prank. Felt a little bad about wasting the IT guys time.