I hope this is in the right section. 
If you already know Hiragana and Katakana and you want to keep up-to-date in a fun way, this website has several games where you can practise your knowledge:
http://www.learn-hiragana-katakana.com
The only downside is that the Complete Katakana Reviewer features the Katakana for the single syllables, but Hiragana for the compound syllables.
But the other games are well worth a try.
If you already know Hiragana and Katakana and you want to keep up-to-date in a fun way, this website has several games where you can practise your knowledge:
http://www.learn-hiragana-katakana.com
The only downside is that the Complete Katakana Reviewer features the Katakana for the single syllables, but Hiragana for the compound syllables.
But the other games are well worth a try.