[biophysboy]

I've been using spaced repetition software (Anki) to learn Japanese. Community decks are really powerful for the basics, but personal decks are unavoidable later on.

For language learning, there are flash card generators that make this a simple one-click process. I think these strike the right balance of simplicity & flexibility/personalization. Of course, a tool like this relies on a free database that you can map concepts onto. But I could see this sort of working with wikipedia or some documentation.