One thing I do when I'm interested in something is to buy books on the subject, or in the case of languages, books in the subject. For example, I've occasionally re-read a favorite book in French (e.g., La Stratégie Ender or Ender's Game, Escadrille 80 or Going Solo by Roald Dahl). I know I'm interested in it, and I know the basic story - pretty good practice.
I wish I could do this in Japanese, but unfortunately I never learned to read above maybe the second grade level! If you know 200 kanji, that's great for signs and menus (where many words are in phonetic hiragana and katakana anyway), but it's less than 10% of what you need to read adult materials in Japanese. So I have tried to find material intended for children that is still somewhat interesting, including a few classic children's books and some non-fiction materials that include pronunciation cues (furigana) for the more difficult kanji.
I haven't done this for a few years, but today I bought a couple of books and a magazine on space and astronomy subjects. One is Uchuu Ryokou ni Ikou (Let's Travel in Space), which features many extensively labeled diagrams and photos of spacecraft, launch vehicles, astronauts, etc., making it possible (with the many furigana-labeled kanji) to learn a lot of space terminology in Japanese. I also bought a 2008 sky guide for young astronomy enthusiasts, and the January issue of a Japanese astronomy magazine for adults, Hoshi Nabi - too hard to read much, but great pictures, including a nicely illustrated article on the Japanese SELENE (Kaguya) moon probe.
The final purchase is a book of color stereo photo pairs of various Hubble images. I can't quite fuse the images with the with the built-in stereo viewer yet, but I'll figure it out. The author has an interesting web site in English, Inaka's 3-D Space World. Of course the real question is when I will have time to read and learn all this stuff.