I can't remember, and i can't find it in my manga * piles of manga spilled everywhere *. i think it was about something about a record, and syaoran goes ' i didn't hear about that' and Yamazaki says he should have remembered Syaoran was from China.
Anyways, my favourites are the one when he lies about Badminton in the third book, and Syaoran and Sakura face off for ages ^^ he he.
i also like one in the anime, the 'running of the strawberries'. love it.