The extra money that you pay when buying a Mac as a opposed to a computer with the same specs from another manufacturer. Some people consider the Mac tax to be a good trade-off, others do not.
"My new iMac was 1500 bucks."
"WTF, why'd you pay the Mac tax, you could've gotten a Dell for like half that."
"Um... Because now I have an operating system that works, from a company that doesn't have monkeys for tech support?"
Device for instantly killing computer equipment: an Ethernet jack on one side, spliced to a power cord on the other end. When plugged into an internet port, floods the computer with electricity, thus destroying it. Invented by the BOFH (Bastard Operator From Hell) from Simon Travaglia.
The IT guy was pissed off about being fired, so he took his etherkiller from router to router, frying them.