Almost two years ago, I blogged about this wonderful site where you can test your English vocabulary. I stopped playing it after a while, and I think the site even disappeared for a time, but it's back and even better. The English vocabulary section is pretty much the same as it was before, just with the words distributed among more levels. And now there are other subjects, including art, chemistry, geography, English grammar, and foreign language vocabulary.
The English grammar quiz is pretty easy and there are only five levels; I got bored with it fairly quickly. The foreign language vocabulary quizzes have ten levels. For Spanish, in which I consider myself fluent, I hit level 10 quickly, as I'd expected. For German, which I took all through high school and have sort of kept up over the years, I could make it to level 10 but mostly centered around 9. I had much more fun with Italian and French, though, neither of which I've studied formally. With Italian, I found that my knowledge of Latin, Spanish, and music got me to level 8 fairly consistently. French is a bit farther from Latin, but combined with my Spanish and all the food-related terms I've picked up over the years, I managed to achieve level 7.
I don't think the database is that large for these languages, so I'll probably play them until I learn all the words. It's more fun than flashcards.