A couple of weeks ago I found a great page. It basically was a level based SQL game. Starting off with simple queries you earned stars by completing tasks. The exercise declaration featured information about a certain database and what tables it features. You had to write statements/queries in the browser and solve the problem. The exercises got more and more difficult.
I already used Google and the search function at Stack Overflow and skimmed through hundreds of pages but couldn't find it again!
ps: its not sqlzoo! the page was black and had a decent design!