I'm usually inspired by what-ifs. My muse is demented, so they tend to be interesting what-ifs. I can be inspired by anything from TV to movies to books to fanfiction, and even some computer role-playing games if they have a decent plot, like Baldur's Gate, Icewind Dale, and Morrowwind. Music sometimes inspires me.
I've been inspired by factual events as well as fictional. Heck, I've even been inspired by a reference book once (ok, it had to do with Norse mythology).
Nature can be very inspiring, particularly when I'm up at my parents' cabin on the lake. I've found that it's easier to be inspired by nature when you're closer to it than in the city.
Life experiences can be inspiring as well. Some original characters have been at least partly inspired by people in real life. Well, bits and pieces of them, obviously.
Anything can be inspiring. You just have to let inspiration come to you. :
