If you read that sign, and then went back and read it again, you're not alone. You could literally bet your house that this is a second hand joke passed on while sitting at a bar pounding down a few beers. Someone tells it, another person thinks its funny and then it ends up on the front of a sign for a self storage place in Canton, Maine...
Lucky for you and I, this guy had the time to sit down and figure this out and record it. See how many classic bass lines you recognize in this epic video.