You know Uno the card game right? Well, Nippon Ichi, is the Japanese Kana card game which has very similar rules to Uno. Instructions are included in the file.
This game will teach your students both Hiragana and Katakana. It is appropriate for students of all ages. You can use it as a filler and as a formal activity for the teaching of kana.
Have fun with it. Your students are waiting.