What to write when your mind is empty?

Not creatively but inspirationally, what is there to do then?

I've tried long and hard to find something to write about, but I am seriously lacking inspiration, I have so much to say but I have nothing to say it about, is as if there was nothing for which I felt passionately about.

The last thing I wrote, was in a way commissioned to me by the girl with whom I am in love. She dared me to write for her a story based on a song by her favourite band, and so I did, and the result was a beautiful yet tragic tale. 

In the writing of that story, I found that what I need is a muse, a muse like her, that dares me to be better, to imagine, to create new worlds, and maybe deep inside myself, that's all I want to do, to only create new worlds for her.