At least

As we crossed Constitution Avenue with all the people that have ever lived on this or any other world, my father and I heard a guy in his 20s remark to his friends, "There have to be at least a thousand people here!"

My father and the guy's friends and I all laughed, a lot, which inspired him to try to improve on his original success ("Hundreds!" "Dozens!"), but really, you can only nail something like that once per audience, and he got it the first time.