For the past week I've been showing some classes a website produced by England's BBC. It's called Skillwise, and features several pages of games that are, for the most part, quite well done.
On the third page of the "English Games" section you can find a syllables review game (all of my students like it, though it's a bit slow), several "treasure hunt" games to review verbs, and an advanced murder mystery game called "The Big Scan".
I completed the mystery game last night with a middle school class (the game took two classes to complete), and they liked it, though I think they were a bit overwhelmed with all of the details.
Anyway, the site is worth a look.