I learned about Knoword through Free Technology for Teachers. This is the way Richard Byrne describes the game:
"Knoword is a fun and challenging game that tests your ability to match definitions to words. Knoword is played like this; you're presented with the first letter of a word, its part of speech (noun, verb or adjective, for example), and the definition. You then have to fill in the correct spelling of the word. If you enter the correct word, you earn points. If you don't get it right, you lose points.
You don't have to register to play Knoword, but you can register if you want. Registering for Knoword gives you the option to keep track of your game statistics. Registered users can also earn badges based on their performances."
The only downside with Knoword is that it doesn't seem to work properly with Explorer, unless you have Explorer 9 in your system. They recommend all the other web browsers -Mozilla, Chrome, Opera, Safari.
