agents and positive responses

OUt of idle curiosity (or not so idle), for those of you who have an agent or have at least gotten a request for more out of your query letter, what is the SLOWEST amount of time that has elapsed between sending your query and receiving positive response? I know rejections can take forever, but I wondered if positives were the same and varied or mostly quick...so random poll, lol! (Can you tell I'm in "waiting" mode, haha!)