Being an ex-band roadie and now a church sound guy, there have been times when I have had to make adapters on the fly. Seems like there are always two things that need to be connected with different types of connections, and troubleshooting problems can be difficult if you don’t know what hooks up to what. [...]

This is a typical diagram of how to connect 2 switches to the same light. It’s especially handy for stairs, hallways, and big rooms.
You will notice that the power feed goes into one switch box, while the switch leg (light wire) goes into the other.  There is also a “traveler” line that connects the two together.
Traveler:
The [...]