A quiz is the most fun way to find out. Make one in seconds, send the link, and let the bragging rights begin.
Under the heading Who knows the most? on the front page: making a quiz and sending its link to see who knows most. "Let the bragging rights begin" is playful: the fight for the honour of winning starts, so use the language's own idiom for it
Galdetegi bat da jakiteko modurik dibertigarriena. Egin bat segundotan, bidali esteka, eta ea nork janzten duen txapela!