Unlike most computer games, which are intended just to entertain you, there are other games like WordGrid that also have an educational purpose.
WordGrid is a word game that challenges you to build as many words as possible with the letters you're given at the beginning of each game. The longer the word, the more points you score, as each letter has an assigned value in points. The only requirement is that the letter tiles must next to each other in order for you to be able to use them.
When you successfully build a word, used letters disappear from the board and you simply have to keep on building new words until you run out of letters.
For the vocabulary-challenged, WordGrid features special tools to make the game even easier. You can set it to suggest words (which appear when you hover the mouse over the word you're building) and also use three blank tiles as extra tiles that can help you build a word.
The best thing about WordGrid is that it not only helps you improve vocabulary in your native language, but can also be used to learn words in a foreign language as it can use different dictionaries - though you'll have to download them separately. On the downside, it may get boring soon if you only play against the computer.
Expand your native vocabulary and learn new words in other languages with WordGrid.