So my computer is kind of busted right now. The "z" key has been intermittently sticking for the past year or so; it was never a physical issue, though, and I could actually double the rate at which my computer spewed the letter "z" by holding the key down.
As of last night, though, it started disgorging z's within seconds of logging on. The same happened in Ubuntu and a live boot of Debian, so it's not malware or something.
I've potentially found a solution that involves FilterKeys and taping the "z" key down when starting the computer, but it's still pretty obnoxious. At least I can use the flipping thing.z
zZBOLZLOCZKSZzzz