They made a lot of references during the earlier seasons of Family Guy. One was where Brian had asked an orchrestra to play the music where the Brady Kids all come down the stairs during the episode where Peter had opened up the church in the name of The Fonz to impress his dad.
And there was another episode, though I forgot which, where Peter mentioned the Bradys and it showed Mike putting either Greg or Peter (second son) into a flaming closet for getting into trouble.