Loving “wordsquared.com“, and recommend everyone tries it at least once, very accessible and it’s such a simple, but clever idea.
It’s similar to Scrabble, except you play against everyone else in the world at once, on an infinitely growable board!
It’s hard to fully explain, but try it and I think you’ll be impressed!
(For the geeks amongst us it’s one of the first, large, applications to be created using “Node”, a new web application development platform, which specialises in realtime communications & rendering, which is how I stumbled across it)