This is a script that will play a random sound from the directory you specify on your mac, with the likelihood you desire.
Typical usage is in a cron, such as this:
* * * * * /usr/bin/backup.py -o 20 /Users/simplegeosf/farts
This will run the script every minute, with roughly 1 in 20 executions resulting in an actual sound.
Notice that here the file has been renamed to
backup.py to disguise what it actually does. An even more subversive user might rename the directory containing the sounds as well.