Everyone gets in ruts sometimes - Ive been there.
It's fun to try a different approach to your music, like trying not to sound like yourself.
I've had fun writing metal songs (you can hear one here called Dirty Mud
http://www.myspace.com/burningcandle) and hip hop songs when I'm uninspired.
Or you could try writing music that tries to sound like something looks. I wrote a riff once that sounds like a watertower...
Or you could buy a new piece of music gear to hopefully inspire.