I was just cruising around 20 Meters after dinner looking for some slow-scan TV, and all of a sudden I noticed the band get packed with wall-to-wall signals.
Turns it's the CQ Magazine "WPX" contest this weekend.
The object of the contest is to contact as many different "prefixes" as you can, and exchange a signal report and contact number.
A "prefix" refers to the first part of a callsign, which is where the station is located.
For example, I live in the FCC 6th Call District, so every callsign in Kaliforniastan has a number 6 in it.
A typical callsign would be W6XYZ. Or it could be K6XYZ, or WA6XYZ, and so on. The "W6", "K6", and "WA6" are the prefixes to the callsign, and each would count as a separte prefix.
Foreign callsigns, like "PY" for Brazil, "VK" for Australia, and "ZL" for New Zealand, also have unique prefixes, but also have an additional "multiplier" factored in to their point value in the process of determining your total score.
Contests like this are a good way to make contacts with new countries, but since it's so brief "Roger ZL2ABC, copy 5-9 #444. Please copy my 5-9 #675", and very artificial, many people almost don't consider it contacting whatever area of the world you just "worked".
I'm kind of benign about contests. I operate in them once in a while, but mostly go to the 17 Meter band where contests aren't allowed. I'd much rather TALK to somebody on the radio, as in having a real conversation with them, then just give them a signal report, and move on to the next one.
Sadly, it seems the art of conversation is becoming rare on the Amateur Radio frequencies, as some people just don't want to do anything other than swap reports and say "73".
And that's a shame, given our reputation as "Communicators".