I've actually found a site with some writing prompts to get started on whenever I'm having one of those ever-so annoying bout's of writer's blocks, so incase you're interested, here are a few of my favourites from it!
Begin your story with this line: It was the one thing he coveted the most
List 20 rules you've broken (this one really gets me thinking because I don't usually break rules)
Think about a thing you feel should not have been invented
List the 7 worst things to say to a person who just got dumped
Write from the point of view of a knife inside a thief's pocket
If you want more from the site I found these from, here's the link:
http://www.creativewritingprompts.com/