A double entendre phrase used to express extreme oddity, but can also connote flamboyant homosexuality. The word queer — in its traditional usage — denotes strangeness, and when coupled with the imagery of a football bat — presumably American football — the strangeness is intensified. After all, who ever saw a football bat? What would you strike with it?
Have you met that new guy down in the invoice office with the huge mustache and white denim jacket? He's about as queer as a football bat.