There are some really great apps out there for learning different languages, especially French and Spanish. But there is a shocking lack of apps available for Japanese, and that was a problem when I found out I would be spending time there later this year. I am always on the go, so finding a quick way to pick up some conversational and written Japanese are critical.
Someone recommended MindSnacks, and I am really glad they did. Not only has it helped me to prepare for my trip much more thoroughly than I had been expecting, but it was fun getting there.