I have two kids (6 and 7) that are learning Japanese at school. I'm also learning Japanese so I can help them with homework. My job is making kids educational games, but in my own time (to help out my kids) I made a game to help them remember Hiragana and Katakana. I've put it online so anyone can use it, and will be adding more games as we go along.
Kana Bento - Hiragana game
Hope you find it useful.