I found this interesting and thought some of my fellow skritterers might like to read it too: http://www.theguardian.com/education/2012/nov/09/learn-language-in-three-months
It's about Joshua Foer's efforts to learn Lingala in a brief period of time in preparation for a trip to Congo, and what role spaced repetition played in his efforts.
I think most of us already know this, but a lot of how successful one is depends on doing a little each day rather than a lot in a cram.