One of my favorite creative activities, (you know -- when it looks like you're doin' nuthin' but you can defend it by saying, "Hey! I'm brainstorming!"), is leafing thru publisher catalogs looking at titles. Then, without reading the synopsis, I jot down ideas that the title generates. Often, my ideas are totally different from the actual book I'm looking at. I scribble those thoughts in the catalog margins with a big bold
Sharpie marker, then go back and collect the ideas now and then, collecting them in an idea file.
Of course then I've got to WRITE the darned thing. But it's still great to have a huge file of ideas to comb thru rather than wanting to write something but having no idea what to write ABOUT. (My new grammar rule: It's okay to end a sentence in a preposition as long as it's all caps.