Sit down and make three lists. Edit nothing. Write down everything that comes to mind. Don't censor a thing. If it pops into your head, write it down. Don't get wordy. A one or two-word entry is enough.
On the first list, write every single topic or event that interests you (skydiving, mountain climbing, cave exploring, working in a leper colony, etc.). Keep going until you run entirely out of ideas. Then set the list aside.
Next, make another list. This time, everything that frightens you. (Aggressive homeless people, drug addiction, intimacy, terrorism, zealots, snakes, etc.) Fill up this list and set that list aside.
Next, make a third list – this time, everything that titillates you. Look for topics that you might not even discuss with a close friend and certainly not with your mother. After you fill out all three lists with one or two-word entries, let them rest overnight.
Tomorrow, go to each list and add the things that have come to you since you set them aside. Again, as you do all this, what's important is NOT to edit as you write. If something comes to mind, jot it down. Don't think, "That's silly," and fail to put it on the list. Park it on the list.
Now, once you have done all this, sit down with the lists and find the ideas, concepts, or notions that MOST interest you, most frighten you and most titillate you. Strikeout the entries that you find little interest in. Carry those shortlists around with you for a few days. Look at it often. Let your goal be to explore ways you can integrate these most compelling topics from each list, give them to a character as a problem or goal. Be open to random ideas that jump to your mind. They will come.
I promise you that from this effort, you will come up with the seeds of a story:
a. That you want to write,
b. That frightens or excites you,
c. And will energize you to write.
It may come in the form of where your story will take place, what the problem or challenge is, what's at stake, and/or how your yet-unnamed character is completely unqualified or unprepared for what's ahead. At that point, the job gets a whole lot easier because you now only have to figure out who you would put in this new world to accomplish what it is he must do (or rid himself or escape) and who will stand in his path.
Give it a shot. The lists are the catalysts that will draw you to some particularly appealing or magnetic areas you hadn't considered before.