I propose Advent of Outage: just pull a random plug in the server room every day.

How about something like

    while [1]; do kill -9 $((rnd * 100000)); sleep 5; end

Probably needs some external tool for the rnd function.

On a serious note, I just saw this: https://linuxupskillchallenge.org

Bash has a built-in RANDOM.

  while true; do 
    kill -9 $RANDOM
    sleep 5
  done

Or to kill running running PIDs each time

  while true; do 
    rnd=$(ps -e -o pid= | shuf -n 1)
    kill -9 $rnd
    sleep 5
  done

That's hardly an "upskill" imo. You would know almost all of it by running a linux server for a month or two

I haven't set up an advent event (maybe I should) but you can do yourself a challenge a day from SadServers.com