I few months ago, I discovered something called the Free Dictionary (by Farlex). There's nothing else I've found that has as good of an Idiom Encyclopedia/Thesaurus as this. I use it often, when the doldrums of the same-old idioms set in.
While before I stated before that it was "as useful as Wikipedia," however, I request your permission to change my tune. The only thing it has over Wiki is the games below. I have left them here on this post (even though I've recinded the rest of the post) because many people have stated it's their favorite part of the day.
Have fun, now.