Here is another but I don't know that answer to this one. This is from Rabbi Reisman's weekly Parsha shiur that is emailed out to thousands of people. He asked this question last year on Shabbos Hagadol, but I never got the following week's paper to know the answer. I'm assuming it has to do with Pesach.
"One more riddle for which you have to know a S’if in Shulchan Aruch. How is it possible to eat one Kezayis of Kosher food and eating that Kezayis obligates you in 20 Berachos because you ate that Kezayis? The answer will be told IY”H next week."