A week or so ago I decide to relearn hiragana and katakana (Japanese syllabaries), which I'd completely forgotten. I loaded a hiragana flashcard set onto iAnki (read Gary Wolf's excellent Wired article about the guy who invented the memory technique that iAnki employs) and went to work. Progress was brutally slow.
I looked around the iTunes store and came across Dr. Moku's Hiragana Mnemonics. It presents each character as an appealing and memorable cartoon - a rabbit eyeing a carrot, a dude with food, a farting cow. Each flashcard is a different color (to "refresh your brain" with each new character). Thirty minutes later I had memorized all 46 hiragana. Now my 9-year-old is learning them, and having a lot of fun. (of course, learning to write hiragana is going to take much more time).
Now it's time for Dr. Moku's Katakana Mnemonics.