Have a look at the prompts from last month's
contest thread and see if anything inspires you. There are plenty of old writing and poetry prompts in the Creative Corner, too.
I've been told that not being excited about writing a scene or a story means that subconsciously you know there's something wrong with it. Maybe try a smaller project and just keep ironing out characters and plots until you find something that works for you. You can do pretty much all of your brainstorming and swap ideas around as needed before you ever commit to the actual writing part.