Personally I try replacing photography with another hobby completely for a little while. Usually I will focus on reading, drawing, working on my car, etc. When it comes around to it, I will usually stumble across a photograph on the internet that reignites my passion for photography.
If at first you don't succeed, give up :D
I pick up my guitar and play...
Think about other people for a change. Think of the nicest thing you could do for a friend, partner, parent, colleague, brother, sister etc and plan it thoroughly and do it. I think there is a lot of wisdom in that old adage in giving, you receive. We are living in a remarkably self-absorbed age. If we gave some more thought to others' ruts maybe we wouldn't get into our own?
I'm like an old pugilist. Put a rangefinder film camera in my mitts, ring the bell, and I'm ready for the next round.