There's a brand new free and educational game available on Sourceforge. WeiLiYu, which translates as Feed the Koi, is an educational Java game designed to freshen your pinyin and Chinese reading skills.
For those not versed in Chinese, pin means "spell" and yin means "sound." So, in essence, pinyin is the western phonetic mapping for Chinese characters.
The gameplay of WeiLiYu is simple - you earn points by typing the pinyin equivalent of the Chinese characters each koi wears on its head as it swims across the screen.