I usually get my ideas from the weird places that my mind wanders to. My train of thought tends to skip around on the tracks a lot. Seriously, I can go from thinking about tacos to wondering the half life of cobalt in 10 seconds flat.
The idea for Venus In Furs came from my own facination with ware-creatures. I'm one of those silly people that honestly believe that it's possible to change into another creature, or at the very least, that other creatures besides monkey's are our ancestors. Think about it, how many people have you looked at and thought "Gee, I wonder if there's horse in that Gene Pool?"
That's part of the problem of having a brain that dosen't shut off. it's constantly hoping from one topic to another. Makes it very hard to concentrate.