Well, only the first one is a trivia question, but you'll get the idea (answers are below)
1) Where do the modern wire guage designations come from?
2) Troubleshooting.... In a home, you have about half of the circuits without power. Upon checking the breaker panel, you determine it's EVERY OTHER BREAKER that's without power, but none of them are tripped. What's the problem?
1) Wire guages are derrived from the old days, when the only way to get smaller wire, was to run it through the wire forming machine more times. Therefore, a "0" guage wire was the largest, a "12" guage had gone through the machine 12 times, a "22" guage had gone through 22 times, etc.
2) Most modern homes are powered through multiple 110 volt feeds. The way current is generated/transmitted, is far beyond the scope of this board, but basically, there's three, 110 volt wires running from pole to pole (or underground), and each home is usually powered by two of these. Since most circuits run on 110, only one of these feeds is used. But, to help balance the load, circuit breaker boxes are designed such that every other individual breaker is powered by one or the other of these 110 volt feeds. To come-up with the 220 volts needed by high power devices (A/C, electric stoves, electric water heater, etc), the breaker actually bridges both feeds, thereby receiving the 220 volts.
Hope this has entertained/enlightened some of you.