Other than the typical activity with Incremental Reading (I am really enjoying reading novels), I had a recent epiphany when using Pimsleur Hindi: it is not very difficult to get the bare basics of a language down (Using Pimsleur or other programs), and by using SuperMemo you can easily retain all of your progress. In other words long as you "back up" your progress using SuperMemo, there is no risk of EVER losing your hard-earned progress.
After finishing Pimsleur Hindi Comprehensive (And not relying on ANY other study materials during the time), I cannot say that I am fluent in the language. However, I now have a basic working knowledge of Hindi grammar. A few weeks ago, I didn't have it. Now I do. "That's pretty neat," I thought.
I hardly consider myself an expert in linguistics or learning languages; I can only base my conclusions on my own experiences. But for the last three languages I've started learning, while Pimsleur didn't give me fluency, my experience has been that it has constantly provided me with a solid first step in each language. Like a "starter deck" in a collectible card game, Pimsleur is a nice "starter deck" for a language.
Over the last few weeks, my listening routine has changed slightly: Rather than making flashcards the first time I go over the material, I constantly keep an iPod Shuffle (A small iPod with a clip on it) with me that has only Pimsleur lessons on it. When I have more than 1 or 2 minutes of free time, I plug my headphones in and listen to the lessons. If I have trouble coming up with the correct responses taught in that lesson, I repeat the lesson again. Usually by the second or third listen even the most difficult lessons "clicked."
After I finish a few lessons, I make sure to add any notable phrases to SuperMemo. I do this by listening to the mp3s again on my computer using VLC (A really nice video and audio player for the PC and Mac). Because I have already heard the lessons before, I can speed up the playback without negatively affecting my comprehension. Thus, I have been re-listening to sped up lessons, pausing the lesson when a new phrase is introduced (Or one that I recall struggling with), put the phrase into SuperMemo, and move on. One 30-minute lesson can be covered in 15-20 minutes when sped up.
When I keep my iPod constantly attached to me, I am able to listen to at least one or two lessons per day. Driving to work, fixing a leak in the basement of my house, brushing my teeth, I was surprised at the amount of free listening time I had on my hands. It hasn't added any stress to my life, the only thing I have had to change is my listening habits (And the time I spend creating the flashcards, which is not very much). The flashcards added to SuperMemo are very easy-to-remember because they have already become a "stabilized" short-term memory.
This process has worked for Pimsleur Hindi, and over the past couple of weeks I have been going through Pimsleur Korean I (I am on lesson 15). I have had no problems recalling the phrases introduced, and I have made quicker progress on the Korean lessons than Hindi (Which I think can be attributed to a better structured listening and reviewing routine). As long as I can continue at this pace, I plan on using Pimsleur to learn the basics of as many languages as possible over the next couple of years. Pimsleur's catalog is quite big, and I plan on finishing every "comprehensive" course they have.
I'm not trying to show off or brag, but I am pleasantly surprised at how such a small change in my life (Listening to audio lessons instead of Japanese indie music or entertaining podcasts) can net such a positive result (And hopefully many more positive results in the future).
The main reason I think this is worth doing is because I absolutely love people; every person you meet has a unique backstory, likes, dislikes, aspirations, etc. I would love to communicate with as many people as possible. Thus, I have recently begun a new long-term project: relate to as many people as possible by learning as many languages as possible, and using Pimsleur as the starting point for each language, and keep doing this until I die.