If you've been wanting to brush up on your foreign language skills but can't devote much time to studying, a new Chrome extension might be just what you're after. Use All Five and the Google Creative Lab have launched a Language Immersion extension that intersperses text on the web with random words from one of a number of languages. You can select the frequency of foreign words on a sliding scale from novice to fluent, and they show up in your text highlighted in blue — clicking them instantly reveals the translation in your native tongue.
The list of supported languages is pretty long, though for some reason it doesn't work with Japanese right now. Given the well-documented problems with machine translation we wouldn't take this as a solid resource for studying complex grammatical structures, but it could well be a handy tool for boosting your vocabulary.