This is actually a topic close to me, about an anthology called Machine of Death. It has a long history that all started from this comic that posed a rather interesting writing prompt to the masses of the Internet. Suddenly, there was an open call for short stories and the Machine of Death came to be, in both print and ebook format. It was self-published by the editors and is an amazing exercise in how hundreds of people can independently write such varying stories all thanks to a T-Rex.
What's most interesting is that you can actually download the ebook for free, right now. The creators describe their thought process behind this here, and it's a really interesting concept. Since they don't really have to answer to a big, faceless publisher, they can feel free to offer this book without having to consider printing costs and the like.
Thanks to the success of the first book, they've since held another open call for stories and published a second book on the idea, called This is How You Die. Unfortunately, since they did have to go through a publisher, TiHYD is not available gratis. I'd still recommend both books for those who would be interested in the concept.