Aside from publication, getting an idea for a story is one of most favorite parts of the writing process.
Okay, I love all parts of it, but there is a special chamber in my heart reserved just for ideas.
There is a great feeling when you come up with an idea for a story. Where this comes from, I don't know. It feels like, to me, as if a Higher Power--once again, I call this God--has tapped me for a special project. I know how absurd that may sound, especially if the idea is filled with blood and gore, but the feeling is unmatched by most other feelings.
When I came up with the idea for Beholder's Eye I got a chill down my spine and spent the next five minutes throwing ideas down on a page. This was odd for others to watch, because it was minutes before a class was starting and the fellow students around me were wondering what in the hell I was writing, for the instructor wasn't even lecturing yet.
Some ideas unfold and blossom right before my eyes while others take a lot of work to uncover.
My suggestion is to keep a notebook handy at all times and write down every single idea you come up with. Who knows, you could come up with one idea, not have anywhere to go with it, and come up with another idea a month or so later that fits with the first one . . . and pow!