I don't understand this. Is it supposed to be a joke?
Native speaker’s answer
Rebecca
Yes, this sentence is meant to be a joke. He is explaining to her that the place where he lives is boring, and the most excitement that people get there is a new "please be quiet" sign in the library. This is a joke because a "please be quiet" sign is not usually something that people find exciting. So he uses this to express just how boring it is there.