Near the top of most of my website pages you’ll find links to several online translation programs (I recently added two or three more). Students use them on occasion to help understand difficult words or passages if none of their other strategies work, particularly in content areas.
The ones that I link to are Babel Fish (probably the oldest and most popular of the online translation programs); AjaxTrans, World Lingo, Google Language Tools, and AOL Study Buddy Translator.
Since students use them so seldom, I’ve never bothered to ask them to rate their quality. I’d be interested in hearing other people’s opinions if you care to comment.
You have commented on the motivating power of computer games. A little anecdote I would like to share. A grade 6 kid wanted to hack the computer code of a game coded by a Dutch programmer for GameMaker. He loaded the source code into BabelFish and translated from Dutch to English so he could see where to increase the range of his laser turrets!
This is the kind of motivation to learn which a relevant and authentic challenge produces.