Also the matching words shouldn't be passed to the client, keep as much data server side as possible to elevate some of the cheating, your never going to stop all of it but that should deter most people.
All in all though kudos, looks a decent outcome for a hack project.
Edit: You might want to change the page's title. Also, thanks for the game. I really enjoyed it.
edit: aaaand someone crashed the server :/
Also, I was hoping there would be more to it - like an all-time high list, or something like that. I'm not sure how you would structure it, but I think some kind of stored history would make me want to come back and play again.
What did you use for the server side? First I started with a Java server with sockets but I noticed that it does not work behind the firewalls and now I am using PHP as a messenger between the java server and flash client. Since flash is now only doing HTTP requests it should be fine with firewalls.
Also did you pregenerate the boards? I generated some but they are not very good.
BTW you could probably come up with something prettier than a JS prompt to ask for a name.
I've been making a game and using Heroku, but when I started doing multiplayer, I realized Heroku doesn't support socketio.