I've been helping someone at another site hook up with some online word- and spelling-games. (They'd been mislead into using the trial download versions instead of playing the streamed flash versions.)
The two games my learners make the most use of are Bookworm @ Yahoo and Text Twist @ Yahoo.
There are comparable games among the Facebook apps Scramble and Word Twist, but I can't say I'm a fan of these. (Why do Facebook apps always seem to want you to spam all your contacts, publish your results, and generally do four other things rather than just play the game?) Michael Chalk from down under has a post about these games (as well as many other things - he's connected with the PRACE crew). Other than that....
Despite the hype and the promise, there are surprisingly few easy-to-access, high-end word and spelling games out there that are both suitable for adults and free.
Anyway, if you haven't tried the Yahoo games, give them a spin. If you know of another you'd like to share, let us know. Comment, or, better, post and put your link in the comments.