Hamtaro Ham-Ham Challenge (Tottoko Hamtaro Nazonazo Q: Kumonoue no? Shiro in Japan) is a Nintendo DS video game by AlphaDream and published by Nintendo (Japan), 505 Games (Europe), and Natsume (America). It was first released in December of 2005, around the same time as another AlphaDream title, Mario & Luigi: Partners in Time. The game takes place after Princess Hatena is kidnapped by a gang of thugs on the day she was supposed to become queen.
In the game, you'll answer riddles that are given to the player. In order to beat the game completely, you'll have to beat 450 riddles. The riddles were made not only by Nintendo, but also by contributors who visited NCL's website. After you complete a riddle, you'll go onto the next one.