Interesting, here in New Zealand, the current weetbix advertisments claim that the four of the All Blacks, sporting legends in New Zealand's eyes can only eat totals of 4, 5, 6, and 8 weetbix (admittedly they were only kids, but I could eat 12 when I was young).

A party trick is to get some gullible fool to eat a dry weetbix as fast as possible, and attempt to make them laugh as they do it for an entertaining sight!