Wordle This is a tool for producing word clouds. Feed it some writing, and it’ll spit out a purty picture made of words. You can adjust the size, font, colour and orientation of the words in the cloud, and I’ve had a few of these on my wall in the past (you can use “print screen” to save your images). It’s not just for show, however: more frequently-used words appear larger in the cloud, so by pasting in some of your writing you can get an idea of what sort of vocabulary you use (and abuse).
The Universal Mary Sue Litmus Test You know that character of yours that all your other characters love and who’s super special and has rainbow hair and magic powers and a pony? This site has some bad news.
TVtropes A Wiki dedicated to cataloguing tropes not just from TV, but from film, games, literature…even real life. The ability to deconstruct an existing story is an enormous help when creating a new one of your own, but be warned: TV Tropes Will Ruin Your Life.
BookCrossing “The World’s library.” If you’ve got way too many books and just can’t bear to say goodbye to any of them, this might be just what you need. Print off a sticker (bearing a unique code), slap it onto your book, and leave the book somewhere for someone else to find. That person can then log where and when they found the book, and (when they’re done with it) leave it somewhere for somebody else to find. You’ll be able to track your book’s journey from the BookCrossing website! It seems to be big in Germany.
Twine A fantastic tool for producing interactive fiction. I thoroughly recommend giving it a go–it’s really easy to pick up right away–but to get the most out of it, you might want to check out this website too.
Stereomood A site that categorises music by “mood,” and will provide you with a playlist to match. The appropriateness of its selections can be a little hit and miss, but it’s a great place to stumble across some new tunes.
world.deviantart.com This is a thing that exists.