After seeing this article (link expired), I tried to make nightbot to give me a random response from !favorites using this:
$(eval a=$(urlfetch json https://twitch.center/customapi/quote/list?token=5fedcb87&no_id=1);a.startsWith(~)?a.split(~).filter(c=>c!=`).join(,)[Math.floor(Math.random() * a.length)]:No favorite found.`)
But apparently it give me a random letter, not the entire phrase.