If you feel confident with how many words you know, then you should really try Word Story, a game where you can put your vocabulary skills to the test. In Word Story you have to form words with the letters from the screen if you want to advance to the next level. The catch is that the letters you get are random, and the word you have to form with them is also random. These constraints will really challenge your skills and keep the game fun for longer periods of time.
And another way Word Story keeps things fun is that it won't let you put the same words over and over again, and it asks that you try to find new words that you haven't placed before. Like you probably would expect from a game that tests your vocabulary, the atmosphere is relaxed, and you won't have to rely on your hand-eye coordination.