The other day a fellow teacher blogger posted about a lesson using AIM or IM language and translating it into standard English and back again. I was at school and couldn't link to the website where he got his idea.
Of course, now I'm at home, and can't remember the site or the blogger.
I found it! This is the post I was talking about. Mr. McNamar was the one. I printed out the 10 (!) pages from the BBC Adobe file, and now am going to go about adapting the stuff for my classes.